Emit a stop point before a call expression so that debugger has some chance of gettin...

Emit a stop point before a call expression so that debugger has some chance of getting some footing when user wants to stop at 2nd bar() in following expression when all function calls are inlined.
  = bar() + ... + bar() + ...

clang keeps track of column numbers, so we could put location entries for all subexpressions but that will significantly bloat debug info in general, but a location for call expression is helpful here.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127018 91177308-0d34-0410-b5e6-96231b3b80d8