memunreachable: prevent forking when main thread times out am: 0b1e8d31d2

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/memory/libmemunreachable/+/18358671

Change-Id: Ibdc74fac40d9b42bc4cffc58aa6344c061fa0314
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>