gold plugin: Remap function arguments when creating a replacement function.

When creating an internal function replacement for use in an alias we were
not remapping the argument uses in the instructions to point to the new
arguments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219177 91177308-0d34-0410-b5e6-96231b3b80d8