Handle test excluded from ART MTS uniformly in `regen-test-files`.

Use a `{"<module-name>": ["<test-case-name>", ...]}` dictionary
instead of a plain list to declare flaky tests excluded from ART MTS,
as we already do for tests excluded from MTS (and Mainline
Presubmits).

This is a follow-up to
https://android-review.git.corp.google.com/c/platform/art/+/2306963.

Test: Run `regen-test-files` and check generated files are unchanged
Bug: 167385698
Change-Id: I6cc1b55e3d4338aa9239b342136e74cde66914f0
1 file changed