Add support for post-submit-only ART run-tests to `regen-test-files`.

New Android tests participating in Test Mapping need to have enough
successful some post-submit runs before they are allowed to run in
pre-submit runs. Introduce a new category of "post-submit-only" ART
run-tests to on-board new ART run-tests in post-submit runs, before
they can be promoted to presubmits.

Add recent test `art-run-test-2265-checker-select-binary-unary` to
this set of post-submit-only ART run-tests.

Test: Run `test/utils/regen-test-files` and check its outputs
Bug: 152374989
Change-Id: I95a3d8da13d73f62fb4ff6b11ab4968ef8da120a