[automerge] Fix a bug when getting a gzip header extra field with inflate()....

[automerge] Fix a bug when getting a gzip header extra field with inflate(). 2p: 17292424 am: c362b4c0

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/zlib/+/20545969



Change-Id: I15b7c5e7b981afa87452fc342ff6a9812d7e9f3e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>