Multiple improvements

- Sysprops allowlist now fully moved to the text file.
- Always enable the test timeout w/ improved stack traces
- Add a method to "run on main thread"
- Always enable the uncaught exception handler.
- Tolerate assertion failures on the main looper. (rather than letting
it crash the thread)

- Also some other minor changes needed in my main work.

Flag: EXEMPT host test change only
Bug: 292141694
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: I47b060021ce46b6e9fbe4aca63835745311a4b06