misc: use CHROME_PATH variable in CI and scripts

[r0mflip]

No description provided.

[patrickhulce]

LGTM thanks @r0mflip!

Worth noting that support for this name does still exist in Chrome launcher, but we've just labelled it as deprecated.

[r0mflip]

@patrickhulce Setting $CHROME_PATH alone just makes the script to exit. Even though I use the suggested variable name I would have to set $LIGHTHOUSE_CHROMIUM_PATH anyways. This PR changes that behavior.

Have a look at https://github.com/dump-yard/cbitosc.github.io/commit/029a208abb9f8feb9015ad772c8128a6f95c993d and https://travis-ci.org/dump-yard/cbitosc.github.io/builds/545699626 (ignore the state of the ci and repo)

[patrickhulce]

Even though I use the suggested variable name I would have to set $LIGHTHOUSE_CHROMIUM_PATH anyways

I understand; it's a good update to make us get off the deprecated chrome-launcher variable :) I was just also noting for other readers that this variable name does still work in chrome-launcher even though we change it for our download script here in Lighthouse.

[r0mflip]

I totally understand 😇

[r0mflip]

/pinging @patrickhulce @paulirish