Fix lock logspam for dexoptanalyzer.

Allow dexoptanalyzer(d) to lock `system_file` files, so that it can
lock `/system/framework/$ISA/*.art` files (which is harmless as these
files live in a read-only partition, but admittedly simplifies the
corresponding logic in ART).

Addresses denials of the form:

  avc: denied { lock } for path="/system/framework/arm/boot.art"
  dev="dm-0" ino=1330 scontext=u:r:dexoptanalyzer:s0
  tcontext=u:object_r:system_file:s0 tclass=file permissive=0 […]

Test: Reproduce steps in bug 138683603 and check the absence of SELinux denials
Bug: 138683603
Change-Id: I8a08822b4908b3b37bd0e450dd1356ed92332327
1 file changed