Fix in-place audio format conversion issues

memcpy_by_audio_format() corner case of same format in-place.
memcpy_to_p24_from_i16() for the first sample in buffer for in-place.

Update memcpy_by_audio_format() documentation.

Test: added native unit test format_tests
Bug: 78598192
Change-Id: I9e538ed4ef233b319b846f4a91c27a86eb605a20
6 files changed