Validate input of JNI::NewStringUTF(). am: 7dd48b90bd am: a9780402b4

Original change: https://googleplex-android-review.googlesource.com/c/platform/art/+/13146018

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I2ee2c87dcbb69162538cd4f5b5efe19e4b6a1bc2