Cache binder calls in CompatChanges

Cached call values are kept in ChangeIdStateCache (per-process cache).
Use "cache_key.is_compat_change_enabled" system property to
invalidate the cache (i.e. any value different from the last observed
will trigger an invalidation).
Any process can read that property, but only system server can change it.

Rolling forward the original caching with invalidating the cache upon
package install/update.
Tested fix locally by using the API in SoftRestrictedPermissionPolicy.java,
and running android.permission2.cts.RestrictedStoragePermissionSharedUidTest
which installs some apps with the same uid, which modifies the result of
isChangeEnabled. With the additional cache invalidation the test passes.

ToDo: add CTS test for the caching.

Bug: 140441727
Test: atest PlatformCompatTest
Test: atest CompatConfigTest
Test: atest CompatChangesTest
Test: atest PlatformCompatGating
Change-Id: I0265df1c427b43592e4f4d32fe9cfeb8fbc1bfa9