events: refactor to use optional chaining

[Lxxyx]

Benchmark running on my computer, performance looks good

                                                           confidence improvement accuracy (*)    (**)   (***)
 events/ee-add-remove.js n=1000000                                ***      4.30 %      ±2.08% ±2.77% ±3.61%
 events/ee-emit.js listeners=1 argc=0 n=2000000                            2.90 %      ±3.52% ±4.68% ±6.09%
 events/ee-emit.js listeners=1 argc=10 n=2000000                           1.92 %      ±3.73% ±4.96% ±6.45%
 events/ee-emit.js listeners=1 argc=2 n=2000000                            2.20 %      ±2.87% ±3.83% ±5.00%
 events/ee-emit.js listeners=1 argc=4 n=2000000                           -0.39 %      ±2.89% ±3.84% ±5.00%
 events/ee-emit.js listeners=10 argc=0 n=2000000                  ***      4.52 %      ±2.30% ±3.06% ±3.99%
 events/ee-emit.js listeners=10 argc=10 n=2000000                   *      2.49 %      ±1.88% ±2.51% ±3.27%
 events/ee-emit.js listeners=10 argc=2 n=2000000                   **      2.97 %      ±2.13% ±2.84% ±3.70%
 events/ee-emit.js listeners=10 argc=4 n=2000000                  ***      3.65 %      ±2.09% ±2.78% ±3.62%
 events/ee-emit.js listeners=5 argc=0 n=2000000                   ***      6.47 %      ±2.15% ±2.86% ±3.72%
 events/ee-emit.js listeners=5 argc=10 n=2000000                           2.22 %      ±2.27% ±3.02% ±3.93%
 events/ee-emit.js listeners=5 argc=2 n=2000000                            1.60 %      ±2.92% ±3.89% ±5.06%
 events/ee-emit.js listeners=5 argc=4 n=2000000                   ***      4.25 %      ±2.34% ±3.12% ±4.07%
 events/ee-listener-count-on-prototype.js n=50000000               **     -1.74 %      ±1.27% ±1.70% ±2.21%
 events/ee-listeners.js raw='false' listeners=5 n=5000000          **      3.73 %      ±2.37% ±3.16% ±4.12%
 events/ee-listeners.js raw='false' listeners=50 n=5000000        ***     14.41 %      ±2.32% ±3.09% ±4.02%
 events/ee-listeners.js raw='true' listeners=5 n=5000000                  -2.63 %      ±2.69% ±3.58% ±4.65%
 events/ee-listeners.js raw='true' listeners=50 n=5000000         ***     29.31 %      ±3.29% ±4.40% ±5.76%
 events/ee-once.js argc=0 n=20000000                              ***      7.21 %      ±3.15% ±4.19% ±5.46%
 events/ee-once.js argc=1 n=20000000                              ***      5.66 %      ±3.06% ±4.07% ±5.29%
 events/ee-once.js argc=4 n=20000000                              ***      6.00 %      ±2.72% ±3.62% ±4.71%
 events/ee-once.js argc=5 n=20000000                               **      4.62 %      ±2.93% ±3.90% ±5.09%
 events/eventtarget.js listeners=1 n=1000000                      ***      4.41 %      ±1.93% ±2.57% ±3.35%
 events/eventtarget.js listeners=10 n=1000000                       *      2.75 %      ±2.34% ±3.11% ±4.05%
 events/eventtarget.js listeners=5 n=1000000                      ***      3.50 %      ±1.87% ±2.49% ±3.25%

Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case there are 25 comparisons, you can thus
expect the following amount of false-positive results:
  1.25 false positives, when considering a   5% risk acceptance (*, **, ***),
  0.25 false positives, when considering a   1% risk acceptance (**, ***),
  0.03 false positives, when considering a 0.1% risk acceptance (***)

Benchmark commands: node ./node-master/benchmark/compare.js --old ./node-master/out/Release/node --new ./node/out/Release/node -- events

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[aduh95]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/879/ (queued)

[Lxxyx]

Benchmark Results

No regressions or improvements

                                                          confidence improvement accuracy (*)   (**)   (***)
events/ee-add-remove.js n=1000000                                         1.22 %       ±3.43% ±4.59%  ±6.02%
events/ee-emit.js listeners=10 argc=0 n=2000000                           1.94 %       ±2.91% ±3.92%  ±5.18%
events/ee-emit.js listeners=10 argc=10 n=2000000                          0.49 %       ±2.11% ±2.82%  ±3.67%
events/ee-emit.js listeners=10 argc=2 n=2000000                           0.99 %       ±1.09% ±1.45%  ±1.90%
events/ee-emit.js listeners=10 argc=4 n=2000000                           0.64 %       ±0.92% ±1.22%  ±1.60%
events/ee-emit.js listeners=1 argc=0 n=2000000                           -1.92 %       ±4.05% ±5.39%  ±7.02%
events/ee-emit.js listeners=1 argc=10 n=2000000                           2.49 %       ±3.21% ±4.28%  ±5.60%
events/ee-emit.js listeners=1 argc=2 n=2000000                           -0.64 %       ±4.76% ±6.34%  ±8.25%
events/ee-emit.js listeners=1 argc=4 n=2000000                            3.24 %       ±3.69% ±4.92%  ±6.41%
events/ee-emit.js listeners=5 argc=0 n=2000000                            1.45 %       ±2.08% ±2.76%  ±3.60%
events/ee-emit.js listeners=5 argc=10 n=2000000                          -1.55 %       ±1.91% ±2.54%  ±3.32%
events/ee-emit.js listeners=5 argc=2 n=2000000                           -0.91 %       ±1.57% ±2.09%  ±2.72%
events/ee-emit.js listeners=5 argc=4 n=2000000                            0.31 %       ±1.83% ±2.44%  ±3.18%
events/ee-listener-count-on-prototype.js n=50000000                       3.16 %       ±5.58% ±7.43%  ±9.69%
events/ee-listeners.js raw='false' listeners=50 n=5000000                 0.31 %       ±1.45% ±1.93%  ±2.51%
events/ee-listeners.js raw='false' listeners=5 n=5000000                  0.42 %       ±1.58% ±2.10%  ±2.74%
events/ee-listeners.js raw='true' listeners=50 n=5000000                  0.32 %       ±1.43% ±1.90%  ±2.48%
events/ee-listeners.js raw='true' listeners=5 n=5000000                   3.06 %       ±3.64% ±4.85%  ±6.31%
events/ee-once.js argc=0 n=20000000                                       1.06 %       ±1.70% ±2.27%  ±2.95%
events/ee-once.js argc=1 n=20000000                                      -0.74 %       ±1.13% ±1.51%  ±1.97%
events/ee-once.js argc=4 n=20000000                                      -1.08 %       ±2.29% ±3.05%  ±3.97%
events/ee-once.js argc=5 n=20000000                                       0.25 %       ±1.79% ±2.38%  ±3.09%
events/eventtarget.js listeners=10 n=1000000                              0.08 %       ±6.18% ±8.22% ±10.70%
events/eventtarget.js listeners=1 n=1000000                              -0.22 %       ±3.54% ±4.75%  ±6.25%
events/eventtarget.js listeners=5 n=1000000                               0.16 %       ±4.67% ±6.27%  ±8.28%

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/35422/

[aduh95]

Landed in eb8422c