MediaCodec: clean up resources pending removal at init

Until we can track memory usage in ResourceManager, always clean up
resources pending removal at init so that we can reclaim memory
and any other resources that are untracked.

Bug: 169398817
Test: atest ResourceManagerService_test
Test: atest CtsMediaTestCases -- --module-arg CtsMediaTestCases:size:small
Change-Id: Ia515443379edb03e68dd2ff5cba07c405aacd433