Fix: Use error templates even when reading from stdin (fixes #7213)

[not-an-aardvark]

What is the purpose of this pull request? (put an "X" next to item)

[ ] Documentation update
[x] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

See #7213 for template answers.

Please check each item to ensure your pull request is ready:

• I've read the pull request guide
• I've included tests for my change
• (n/a) I've updated documentation for my change (if appropriate)

What changes did you make? (Give an overview)

This updates bin/eslint.js to treat stdin errors like all other errors. ESLint has a generic process.on('uncaughtException') handler that handles error templates, but previously the code for the stdin flag had its own error handling logic. This PR removes the error handling logic from stdin, which allows stdin errors to cascade to the uncaughtException handler.

Is there anything you'd like reviewers to focus on?

This PR should not be merged yet, as it still needs tests. However, I didn't notice any existing tests for bin/eslint.js. Is there a file with tests that I missed, or should I create a new one?

edit: The PR now has tests.

[mention-bot]

@not-an-aardvark, thanks for your PR! By analyzing the annotation information on this pull request, we identified @nzakas, @shumphrey and @ilyavolodin to be potential reviewers

[eslintbot]

LGTM

[platinumazure]

Hmm. Are there any other tests we can run to try to force other errors (which should have "pretty" output) to be thrown while piping code in? The original discussion is about one use case, so it'd be great to have at least a manual test showing another possible case. (Example: Finding nonexistent plugin, maybe?)

[eslintbot]

LGTM

[not-an-aardvark]

Updated the PR to add some tests for the bin/eslint.js file.

edit: Oops, CI is failing for Node 4 and 5 -- I think the child_process API might have changed in Node 6. Will investigate now. (edit: this is fixed now)

[eslintbot]

LGTM

[nzakas]

LGTM, just would like another set of eyes.