clang-modernize: Fix bugs in Pass-By-Value transform

- Limit the transform to const-ref and non-const value parameters only.
- Do not generate a replacement when the type is already a value.

See CM-139 for the bugs corresponding to this issue.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@190212 91177308-0d34-0410-b5e6-96231b3b80d8