Merge "Add some slack at the end of large allocations when target SDK level < S." am: 6ba27e04df

Original change: https://android-review.googlesource.com/c/platform/bionic/+/1621044

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I4c153c044cfa38e432e3a1e7b6eaca6a7cb8e761