[automerger skipped] stream_decoder.c: Fix a memory leak am: 74bdd1955c -s ours am: d2c4a20a6b

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/flac/+/12736242

Change-Id: I4ac0b958895b884ff9eec736307b2d5b9877dca3