Refactor the parsing of seinfo am: 7fd89c00f7 am: 4bf49f0fb0

Original change: https://android-review.googlesource.com/c/platform/external/selinux/+/2836178

Change-Id: I5b172e06cd5efe1c18a0eb9bf7f69593aeb76d29
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>