src: use internalBinding('config').hasInspector in JS land

[joyeecheung]

Instead of process.config.variables.v8_enable_inspector
which depends on the variable name in gyp files, or detecting
internalBinding('inspector').Connection.

Checklist

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

[nodejs-github-bot]

@joyeecheung build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/2115/pipeline

[joyeecheung]

CI: https://ci.nodejs.org/job/node-test-pull-request/19893/

[jdalton]

What I liked about process.config.variables.v8_enable_inspector is that it's also a user accessible way to detect if the inspector is enabled. Instead of moving to an internal solution it would be rad to expose this in a more user-friendly way.

[lpinca]

I think this should be !hasInspector

[joyeecheung]

@jdalton I personally would not mind if there is an alias for internalBinding('config').hasInspector on process.features, but it would be a separate bikeshed about whether process.features should be deprecated in favor of something newer and shinier and what that might be ¯\(ツ)/¯

[joyeecheung]

Rebased and fixed test: https://ci.nodejs.org/job/node-test-pull-request/19910/

[joyeecheung]

SmartOS ran out of memory. Resume: https://ci.nodejs.org/job/node-test-pull-request/19912/

[joyeecheung]

Landed in b22c86e

[joyeecheung]

Opened #25343 about process.features

[addaleax]

Should this be backported to v11.x-staging? If yes please follow the guide and raise a backport PR, if not let me know or add the dont-land-on label.