[ARM] __cxa_end_cleanup: avoid clobbering r4 am: c0a6edcf3b am: 00928ed8ee am: 4b96903904 am: 9b8c547921

Original change: https://android-review.googlesource.com/c/platform/external/libcxxabi/+/2024827

Change-Id: I68e4af77b1d5ed6a8d303d4531670d896dbb6181