[PGO] RawProf Reader code cleanup

Add a couple of helper methods to make the primary
raw profile reader interface's implementation more
readable. It also hides more format details. This
patch has no functional change.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251546 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed