libselinux: improve performance with pcre matches am: 72806f3933

Original change: https://android-review.googlesource.com/c/platform/external/selinux/+/2411194

Change-Id: I7249eccb5eb1029f753e2d5d2723ce2799ddbd1a
Signed-off-by: Automerger Merge Worker <[email protected]>