mp4_extractor_fuzzer: Dictionary updated

Octal values (\251) were used which was causing error while
parsing the dicitonary and hence updated to use hex
values (\xA9) instead

Test: mp4_extractor_fuzzer -dict=mp4_extractor_fuzzer.dict
Bug: 155663957

Change-Id: Ib11a20145a788504490ef870a67184d84d358609