CTS test spoofed packageName can not bypass BG-FGS restrictions.

Add CTS test case ActivityManagerFgsBgStartTest.java#testSpoofPackageName
to verify framework can stop spoofed packageName from starting FGS
from the background.

Bug: 216695100
Bug: 215003903
Test: atest cts/tests/app/src/android/app/cts/ActivityManagerFgsBgStartTest.java#testSpoofPackageName
Change-Id: I579a3336f3cc9143775540b073558d25f6c08338
Merged-In: I579a3336f3cc9143775540b073558d25f6c08338
BYPASS_INCLUSIVE_LANGUAGE_REASON=legacy API
2 files changed