Revert support libs to 27.0.x, Fixes #4938

[mikehardy]

Using support libs 27.1.x causes cards to not display after screen off

https://developer.android.com/topic/libraries/support-library/revisions#27-1-0

Hopefully I'll figure out why shortly, but in the meantime, the issue is resolved by downgrading the libs to 27.0.x and making sure ACRA doesn't pull them again via dependency isolation in the gradle build.

[timrae]

CI is failing on the Jacoco test report but I guess I'll merge anyway

[timrae]

Wow just checked that link for the changelog, those are some serious changes for a non-api-level revision. The changes to the Loader on the fragment lifecycle could be the culprit.

[mikehardy]

I'm busy reading up on the Loader code and instrumenting it right now as I think the same thing, that has to be it.

The tests are definitely not in a great state right now and I'd never be happy with the current condition of things if it weren't basically a hotfix on an alpha. I know from testing that it does basically work as a build right now, but otherwise yuck.

Next PR will be something that either works fully with 27.0.x libraries (including full testing etc) so we can stay on it, or a clean forward-port to 27.1.x

[mikehardy]

A simple gradle dependency isolation that we were using previously but I thought we could do away with fixes all tests - mikehardy@3dcb4a9 - so I'm not really concerned about stabilizing on 27.0.2 and I'm not feeling a rush there, just pull that and we're all set. I'll slow down and focus on getting 27.1.x correct now but need to attend to RealLife for the rest of the afternoon