Summary computation is not just for instrumented profiling and so I have moved
the ProfileSummary class to ProfileCommon.h (named so to allow code unrelated
to summary but common to instrumented and sampled profiling to be placed there)
Differential Revision: http://reviews.llvm.org/D16661
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259846 91177308-0d34-0410-b5e6-96231b3b80d8
