InputMethodSubtypeArray: prevent negative count injection am: e863b7b828

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

Change-Id: I2b0d82dc1ac33f0c5fc11fb997a3a923099f3d8c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>