Reset buffer managers during reset control call

In some cases, some picture buffer entries in buffer manager were not
released during reset.
Added a function to reset buffer manager entries and called that during
reset control call.
Without this in some call sequences Decoder would run out of picture
buffers and not produce correct output.

Bug: 124531341
Test: atest android.media.cts.DecoderTest
Change-Id: I75e4422263b0a3e66807376567705b1f06e89cff