clang-cl: Don't treat linker input files differently when /TP or /TC is specified.

Summary: This fixes http://llvm.org/PR20923.

Test Plan: This patch includes an automated test.

Reviewers: hansw

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D5334

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217699 91177308-0d34-0410-b5e6-96231b3b80d8