Merge "Nullability check for wctype module." am: 5c6961ff6d

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2626775

Change-Id: I3c1b5b1fed8a5caddb3a5967374beb4f8a243f78
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>