procmeminfo: fix race in IsSmapsRollupSupported am: 422e9a2bff

Original change: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/1607306

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I8a5f0200dcf3e57940e4e6db53d94ce3bf9d4ed8