[DO NOT MERGE] Cleanup TEST_MAPPING disables from ag/9286329

- Moved exclude filters to existing stanzas

Disable CtsProviderTestCases:android.provider.cts.MediaStore_Images_ThumbnailsTest

Disabling in preparation for merge to aosp-master (Q release).

Test: Forrest
BUG: 139535570
BUG: 139305203
Change-Id: I5c7cdb9f308b01d276d34cf9571534908ed5038a
Exempt-From-Owner-Approval: Disabling known failing TEST_MAPPING tests
for AOSP push to Q.
1 file changed