Fix heap-buffer-overflow in MPEG4Extractor

Caused by the extractor assuming that sample size will never exceed
the declared max input size (as in AMEDIAFORMAT_KEY_MAX_INPUT_SIZE).

Bug: 188893559
Test: Ran the fuzzer using the bug's testcase.
Change-Id: I31f2b9a4f1b561c4466c76ea2af8dd532622102a
Merged-In: I31f2b9a4f1b561c4466c76ea2af8dd532622102a
(cherry picked from commit 621f0e12017a2d057aeaa1937e979ce61b2ac3cf)
1 file changed