InputMethodSubtypeArray: prevent negative count injection am: e863b7b828

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/30297781

Change-Id: If805668bd8035b180227e660b77a3847bbc4f14e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>