Reduce RM createResources lock contention

Reduce lock contention for processes that use
ResourcesManager#createResources on background threads by preloading
the apk assets into a temporary cache while the RM lock is not held.

As a result, multiple threads may be performing I/O opening the same
apk assets since multiple threads could be preloading the same apk
at once.

Bug: 111966000
Test: observe significantly less monitor contention with owner bg
      threads calling android.app.ResourcesManager.createResources

Change-Id: Iccf383cb8e1a358af4f71ac242e2216dc5a19ff2