ExtractorUnitTest: add more input vectors

This patch adds different streams like ac4, flac, opus, mpeg2 to increase code coverage for Mp4 extractor

Coverage increase:
Lines: from 34.4% to 55.9%
Functions: from 32.8% to 43.3%

Test: atest ExtractorUnitTest -- --enable-module-dynamic-download=true
Bug: 160111782
Change-Id: Ie6f6709d84809588365404b2821fdea10291f03c