getProcessAgeMs: better error messages am: d9ebe7cef5 am: 9ec25af215 am: 8b4cdbb620

Original change: https://android-review.googlesource.com/c/platform/system/libhidl/+/1459346

Change-Id: Ie3fed06e99f9acd4ee171450f7661b664ff5ad6a