test: mitigate flaky test-debug-no-context

[Trott]

Change test so that it passes on the occasional win10 access violation.

The workaround here can be undone when issue 5268 is resolved.

The test still detects the defect it was written to detect. There are
two assertions that detect the defect and only one was disabled.

Ref: #5268
Fixes: #4343

/cc @bnoordhuis

[Trott]

Stress test showing current version of test is flaky on win10: 15 failures in 100 runs

Stress test showing the version in this PR is not flaky on win10: 0 failures in 100 runs

Output showing the version in this PR fails as expected with Node.js 5.3.0:

$ nvm use 5.3
Now using node v5.3.0
$ node -v
v5.3.0
$ node test/parallel/test-debug-no-context.js 

assert.js:89
  throw new assert.AssertionError({
  ^
AssertionError: 'SIGSEGV' === null
    at ChildProcess.<anonymous> (/Users/trott/io.js/test/parallel/test-debug-no-context.js:18:10)
    at ChildProcess.<anonymous> (/Users/trott/io.js/test/common.js:382:15)
    at emitTwo (events.js:87:13)
    at ChildProcess.emit (events.js:172:7)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:200:12)
$ 

Output showing the version in this PR passes as expected with Node.js 5.4.0:

$ nvm use 5.4.0
Now using node v5.4.0
$ node -v
v5.4.0
$ node test/parallel/test-debug-no-context.js 
$

[Trott]

CI: https://ci.nodejs.org/job/node-test-commit/2258/

[jasnell]

LGTM
@Trott: I assume this is not relevant for v4? If not, can you add the don't land label? :-)

[Trott]

@jasnell Actually, it is relevant. My mistake not labeling it. I've added lts-watch-4.x label.

[jasnell]

Thank you! :-)

[Trott]

Landed in c4b5a45