Basic audio/video encoder/decoder test.

Bug: 32023356
TODO: cleanup the test code b/37719510

ComponentTest :-
1. allocatePortBuffers cleanup
2. More than one test fixture performs State transitions
(Loaded <-> Idle <-> Execute). So, this is moved to a routine and
invoked when needed.
3. Dispatch input/output buffers code section is moved to a routine
4. Seperated Test fixtures StateTransitions_Flush
5. Added Doc string
6. Test component port population

AudioDecTest :-
1. Backport Cleanup changes from ComponentTest to AudioDecTest
2. Added elementary streams for the following codecs mp3, amr-nb &
Updated paths to elementary streams in audio decoder test

Test: Tested ComponentTest and AudioDecTest for mp3

Change-Id: I90decde4dfab55c3d456dfd88b474dd5abe8eebc

List Available components (roles) in android media framework

Change-Id: I210665843e997e60b167f2d680c87b1cc4f90c58

add README.md

Change-Id: I3a2a057d10b18f4f374928a996b8b4ea4b084770

add basic video decoder tests

for a given component test for successful decoding of an input clip

Test: tested for softavc decoder

Change-Id: I2f4c034c34a456e1ed0c2d32ef381ca48aeda8ff

add basic audio encoder tests

for a given component, test for successful encoding of an input clip

Test: tested on softaac, softamrnb, softamrwb & softflac components

Change-Id: I05f5646ffed37143a21ea72f0fd782c2bb5c4d82

add basic video encoder tests

For a given component test successful encoding of nframes of a
raw video clip

Test: tested on softavc encoder.
Change-Id: Ia1d754061e8362f6c08a2be3d6384c95589a36de