Refactored Extractor Fuzzer Plugins

1. Added support to seek and extract tracks in Extractor Fuzzer Plugins
2. Grouped all the common functions together in one function

Test: ./mkv_extractor_fuzzer
Test: ./mp4_extractor_fuzzer
Test: ./wav_extractor_fuzzer
Test: ./mp3_extractor_fuzzer
Test: ./aac_extractor_fuzzer
Test: ./flac_extractor_fuzzer
Test: ./amr_extractor_fuzzer
Test: ./ogg_extractor_fuzzer
Test: ./mpeg2ts_extractor_fuzzer
Test: ./mpeg2ps_extractor_fuzzer
Bug: 156871453

Change-Id: Ie989231c596ec044a5056f02e688d2815c70a3f7