source tarballs does not work without installing eslint

[joyeecheung]

• Version: v9.x
• Subsystem: build

Since #16138 we started to test the eslint rules, which requires tools/eslint to be present, but the eslint is not bundled inside the source tarballs and neither are there any rules in the makefile (or vcbuild.bat?) that try to install one, so those tests will always fail without manually running npm install first.

[joyeecheung]

There are some different options to solve this:

1. Make it install when tools/eslint is not present
2. Make a special test rule for offline testing and skip doc/eslint tests

[richardlau]

Maybe introduce a common.skipIfNoeslint for the tests to skip if tools/eslint is not present?

[kasicka]

Maybe move eslint tests out of parallel and add test-offline to Makefile.

[joyeecheung]

@kasicka Well we do have test-internet though it's not normally run...

[kasicka]

I write faster than I think.. still eslint tests should be moved out of parallel/

[kasicka]

I think this can be closed, fixed by #18807

[cjihrig]

Thanks. Closing.