Coverage Mapping: store function's hash in coverage function records.

The profile data format was recently updated and the new indexing api
requires the code coverage tool to know the function's hash as well
as the function's name to get the execution counts for a function.

Differential Revision: http://reviews.llvm.org/D4995


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216208 91177308-0d34-0410-b5e6-96231b3b80d8