Suppress AppCacheTest tests that cause am instrument failure.

These tests runs a command to clear application data and by
doing so causes the application that is being instrumented
to restart, which in turn "am instrument' thinks is an app
crash, thus aborting the rest of the tests.

Bug: 38238448
Change-Id: Ida69b828a9950a83d790a3a7628e32c14a04a772
Test: bit FrameworksCoreTests:android.content.pm.AppCacheTest