[PGO] Enable clang to pass compiler-rt profile support library to linker on Windows

Summary: This change enables clang to automatically link binaries built with the -fprofile-instr-generate against the clang_rt.profile-i386.lib library.

Reviewers: davidxl, dnovillo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15833

llvm-svn: 256855