[automerger skipped] Add standalone ART gtests to `TEST_MAPPING` group `mainline-presubmit`. am: 506b64c3b0 -s ours

am skip reason: Merged-In I84da85e33c7ac1e44361bbb0b3bfa399ceab9b2f with SHA-1 1de4428db8 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/art/+/15241582

Change-Id: Ic3906cad2d930e3c60cfc4e3748b3edfed1b3c8c