Make compat cache non-isolating

The following cache is no longer uid-isolating:
 * is_compat_change_enabled

The cache constructor has been reflowed slightly to match the latest
non-deprecated apis.

Flag: EXEMPT bug-fix
Bug: 379098894
Test: presubmit
Change-Id: Ifae71807b4599e0ec7f787077c38e6a16f07f2d9