Switch to the hermetic toybox gzip. am: 615a1fced5

Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/2631951

Change-Id: Id08a9422eb10248bbe8f1b184a21b65c5a642217
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>