Reland "Do not create 4-byte sequences in `ConvertUtf16ToModifiedUtf8()`" am: 15ddcab869 am: 6169e75988

Original change: https://android-review.googlesource.com/c/platform/art/+/1762227

Change-Id: Ie09d300ef3243628d8e15d57f062e56ea469906c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>