atrace: enable running on user builds

This change allows atrace to be run on a user build, where it is not run as
root.  Some command line options still require root, and atrace will refuse to
run if those options are specified when run as non-root.

Bug: 6513400
Change-Id: I29984cb8a7c3ad80ba5fa6b031ed8ff81acabacf
2 files changed