Minor Telephony Unit test cleanup fixes

- Simplify Looper initialization code
- Don't catch and re-throw exceptions in
  testWithTelephonyFeatureAndCompatChanges (hiding call stack)
- Use @Mock annotation instead of manual assignment

Bug: 365800992
Test: com.android.phone.PhoneInterfaceManagerTest
Flag: TEST_ONLY
Change-Id: I248cc4267ca543899bbe5f8473481c646130008a
2 files changed