[PGO] Fix a bug in InstProfWriter addRecord

For a new record with weight != 1, only edge profiling
counters are scaled, VP data is not properly scaled.

This patch refactors the code and fixes the problem.
Also added sort by count interface (for follow up patch).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257143 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed