Add test for Instrumentation.startActivitySync()

Actual support for Activity on Ravenwood will take more time,
but let's add a minimal bivalent test for
`Instrumentation.startActivitySync()` as a baseline.

Test: atest RavenwoodUiTest_device
Test: atest RavenwoodUiTest
Bug: 331434971
Flag: TEST_ONLY
Change-Id: I6e601f456fe160f307333fa53d0b55dc48e3d8a8