Disable getentropy on Mac to support 10.10 am: d948d44e88 am: 687d294996 am: 7896ad86c9

Original change: https://android-review.googlesource.com/c/platform/external/python/cpython3/+/1590982

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: If09575358a9cbd0ee7f40cc231f74dfe06c481d1