Add INT64_MIN check in MPEG4Writer sample validate

Sample validation uses abs(timeUs) to check for valid range. If timeUs
is equal to INT64_MIN, the abs() function will cause an overflow.

Test: ndk_mediamuxer_fuzzer
Bug: 323256800
Change-Id: I501c6ac52e52809880f51b67749a88d5cfc86d0c
1 file changed