Fix potential overflow in WAV extractor

Bug: 170583712
Test: fuzzer poc, atest DecoderTest#testDecodeWav
Change-Id: I73edd5fc0da80dc2cdd26c6fcd09496b2c828ba9
Merged-In: I73edd5fc0da80dc2cdd26c6fcd09496b2c828ba9
1 file changed