Fix chrome finder on linux & osx

[wardpeet]

We added priority regexes of LIGHTHOUSE_CHROMIUM_PATH and CHROME_PATH even when they weren't populated so we got the regex {(:?)} which matches everything so the first chrome in the list got hit.

We now do explicit checks to add the regex only if they env params are populated

Fixes #2683

[wardpeet]

Should I create a test file just like we have for chrome-launcher?
introduce the export ModuleOverrides pattern?

[arturmiz]

Oops, my bad... thanks for fixing this as I was the one who introduced this bug 👍

[wardpeet]

@arturmiz no worries 😉 It happens to the best of us!

[brendankenny]

this looks good to me, though it looks like maybe yarn test-launcher-formatting isn't happy? May need to adjust a line break or something.

Related to the code but not this fix, do you mind switching .travis.yml to using CHROME_PATH instead of LIGHTHOUSE_CHROMIUM_PATH?

[googlebot]

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[paulirish]

this looks good to me, though it looks like maybe yarn test-launcher-formatting isn't happy? May need to adjust a line break or something.

fixed

Related to the code but not this fix, do you mind switching .travis.yml to using CHROME_PATH instead of LIGHTHOUSE_CHROMIUM_PATH?

fixed

[paulirish]

thx @wardpeet. saved my bacon!

[wardpeet]

thanks @paulirish for the cleanup