Temporarily exclude Checker tests from ART test mapping.

These tests currently break some ATP (postsubmit) test runs (see
b/169852871), as Checker support in test suites is not complete.

Test: atest --test-mapping art:postsubmit
Bug: 169852871
Bug: 162408889
Change-Id: I39ebb261e64de7207dee21c1ce1ecce0d44e7451
2 files changed