Use posix basename instead of glibc am: 62434518b2 am: f79c211cf2 am: e265ca9bbe am: 7e7e6d3521

Original change: https://android-review.googlesource.com/c/platform/system/testing/gtest_extras/+/1797187

Change-Id: I43caade82606c83477b75d9bc84c34289025c650