Upcoming CI Platform upgrade - Android 7 -> 14 (emulator, not hardware)

[Joel Maher]

I want to announce that we will be upgrading the Android emulator that we run tests on in CI from Android 7 -> Android 14.  One requirement of this is that we need to meet the minimum android sdk version requirements for the google play store which are changing later this year.  

Work is tracked in this bug.

timeline:

 * August 18th - turn ON some tests in parallel in CI

 * continue greening up where possible to enable more tests in parallel

 * September 15th - Turn OFF Android 7 emulator (this will be when nightly switches to v.145)

Currently most test suites only have a few failures, but there are some suites with more widespread problems (will not be enabled until greener, even if we turn off Android 7):

 * junit - under investigation

 * wpt reftest - will disable reference image caching for now

 * xpcshell (debug only)- problem is understood, solution TBD

 * wpt wdspec - TBD

We have the luxury of running some tests in parallel as these run on docker images.  For greening up the tests we will follow the new platform policy.

For more information and questions, ask on #firefox-ci in Matrix.