Container Testing Updates

Summary:
ericvicenti Here is the latest updates and fixes for the container testing. Everything should be good to go now, the update for `inotify.max_user_watches` should fix the E2E test issues you were seeing locally.

The update to the packer prevents excessively large filename lengths due to the hash used in the name and splits them into directories instead. I was getting errors locally on the E2E because the hash filename was over 248 characters which was causing issues on the base image file system. It might not have appeared in circle due to another file system being used with different limits. I can separate it out into another PR if you want though.

* Turned jenkins instrumentation parallelism up to 3
* Disabled various instrumentation tests that seemed to have inconsistent results from
Jenkins by default
* Install google-chrome in the android base image so the chrome debug E2E test does not fail
* Turned back on E2E tests

cc normanjoyner
Closes https://github.com/facebook/react-native/pull/13417

Differential Revision: D4876137

Pulled By: ericvicenti

fbshipit-source-id: 31e033c1e34b02acb5484478414197ac9eb11f95