Better return value checking

clang-tidy warned about unknowability of returned buffer by parameter
after acquire_buffer() calls despite checking return code. Add appropriate
tests.  Wider examination pointed out several places where return code
was not checked and where early out code was missing out on releasing
other buffers.

Bug: 263274255
Test: atest CtsMediaExtractorTestCases
Test: atest CtsMediaV2TestCases
Change-Id: I445808cc58f11321a6cc4a3b615bf352b0b2a419