Refactor the Test Mapping exclusion logic in `regen-test-files`. am: e7f5f064ae

Original change: https://android-review.googlesource.com/c/platform/art/+/2904027

Change-Id: I87b1e643a3f3d373b277b214cd2e0873e5ee7051
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>