Separate caches for separate UIDs

A cache instance maintains one hashmap for each UID making the binder
call.  The UID is give by Binder.getCallingUid().  This isolates the
UIDs but will likely reduce cache efficacy.  Per-UID statistics are
collected.

An individual cache may choose to keep all UID information in a single
hashmap.  This is controlled by a configuration flag to the cache
constructor.  This is also the legacy behavior.

Isolation by UID is flag-guarded.  Statistics collection is guarded by
a separate flag, as statistics turn out to be expensive.

This CL reverts an initial update to the default bypass() method,
since the check for cross-uid cache access is now part of the cache
infrastructure.

Flag: android.app.pic_isolate_cache_by_uid
Flag: android.app.pic_isolated_cache_statistics
Bug: 373752556
Test: atest
 * FrameworksCoreTests:PropertyInvalidatedCacheTests
 * FrameworksCoreTests:IpcDataCacheTest
 * CtsOsTestCases:IpcDataCacheTest
 * ServiceBluetoothTests
Change-Id: I6f3a9df55c820518739814c958a019b04897b42d