process: generate list of allowed env flags programmatically

[addaleax]

Avoids having a separate, second source of truth on this matter.

The second diff is best viewed in whitespace-adjusted mode (append ?w=1 to GitHub URL).

Checklist

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

[nodejs-github-bot]

@addaleax build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/757/pipeline

[BridgeAR]

I would prefer to pass through filter options into getOptions instead of doing the filtering here.
Since it has a string option at the moment, it would likely be best to accept an object for the options instead.

Another alternative to the current way would be to only iterate once over the entries (this is also nicer to read for me):

const allowedV8EnvironmentFlags = [];
const allowedNodeEnvironmentFlags = [];
for (const [name, info] of options) {
  if (info.envVarSettings === kAllowedInEnvironment) {
    if (info.type === KV8Option) {
      allowedV8EnvironmentFlags.push(name);
    } else {
      allowedNodeEnvironmentFlags.push(name);
    }
  }
}

[addaleax]

I’ve gone with the second option for now, but yes, ultimately it might be better to do this in C++ land.

[BridgeAR]

Nit: retrieving the value multiple times is not necessary.

[addaleax]

CI: https://ci.nodejs.org/job/node-test-pull-request/17027/

[addaleax]

New CI: https://ci.nodejs.org/job/node-test-pull-request/17028/ (:heavy_check_mark:)

[addaleax]

Landed in 995782c, d994e26

[targos]

This needs a backport PR to land on v10.x-staging