Merge "Revert "Merge "Revert "towctrans() should return the input and set errno on failure."" into android15-tests-dev am: fd55858120"" into main am: 81132381ff

Original change: https://android-review.googlesource.com/c/platform/bionic/+/3272669

Change-Id: I19933ee3cef5a2ac2c7ab5892b186130c4fbfadf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>