Remove Android test discovery workarounds

[mhsmith]

They're no longer needed now that extractPackages is in the Android template.

Requires beeware/briefcase-android-gradle-template#60: DO NOT MERGE this PR before that one.

I've also added an extractPackages line for toga_android, which should allow #1707 to remove the code that disables coverage on Android.

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[mhsmith]

CI will have to be rerun once beeware/briefcase-android-gradle-template#60 is merged.

[freakboy3742]

I initially had some difficulty getting this working on Py3.10 (log file); but after stepping away and coming back to it, I can't reproduce that failure. I'm guessing I had something stale in my environment, but I can't work out what.

Otherwise - seems to work well.

[freakboy3742]

I've merged up the macOS-probe changes, which also means we now have a coverage report on Android. There is a workaround required because of nedbat/coveragepy#1542.

[mhsmith]

I initially had some difficulty getting this working on Py3.10 (log file); but after stepping away and coming back to it, I can't reproduce that failure. I'm guessing I had something stale in my environment, but I can't work out what.

OK, I've reproduced this now: see chaquo/chaquopy#777.

[mhsmith]

I've fixed an issue with the coverage workaround which was crashing the test thread on desktop platforms, and added a top-level exception handler so the app will exit in such cases rather than hanging forever.

[freakboy3742]

Those changes all make sense to me; 👍