Separate merge from dump and call merge periodically

Every time merge is called by the thread loop,
the data is also processed and written to
PerformanceAnalysis. A call to dump retrieves
the FIFO of processed data in PerformanceAnalysis
instead of the unprocessed Reader FIFO, and prints
the result to the console.

Test: dumpsys media.log

Change-Id: Ic479f48e9e4fdf4523a8f15db514dbdd85b70434