Merge remote-tracking branch 'aosp/upstream-master' into mymerge

Incorporate the latest upstream SELinux changes into the Android
build tree.

  % git merge aosp/upstream-master --no-ff

A followup commit will make Android specific changes to allow
this code to compile.

- Known issue: -

Multiple implementations of partial directory match digesting.

To fix bug 62302954 ("Investigate restorecon() / selabel_lookup()
performance"), Android implemented a number of patches, including
https://android.googlesource.com/platform/external/selinux/+/7d4a56f84d0589c535baa50afceeb70d8a04b856

The upstream SELinux community ended up writing their own variant of
Android's patch, which accomplishes the same thing. This patch is at
https://github.com/SELinuxProject/selinux/commit/e016502c0a265d661a3a4b541b865eec94aae2b1

This merge has the effect of having both patches in the tree at the same
time, which could be confusing. However, the new upstream code isn't
used by Android, so there's no impact (other than code bloat and
duplication).

Change-Id: I2bb804b71763c0c3ba77fe48d42787298f85a9d7
Test: treehugger