[ARM] __cxa_end_cleanup: avoid clobbering r4 am: c0a6edcf3b am: 00928ed8ee am: 4b96903904 am: 9b8c547921 am: d681551325

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

Change-Id: I531f9bd1f54ca6891bd0b7c51241f45915910e3a