[Driver] Don't force .exe suffix for lld

When cross-compiling to Windows using lld, we want the driver to invoke
it as lld-link rather than lld-link.exe. On Windows, the LLVM fs
functions take care of adding the .exe suffix where necessary, so we can
just drop the addition in the toolchain entirely.

Differential Revision: https://reviews.llvm.org/D33923

llvm-svn: 304761
diff --git a/clang/lib/Driver/ToolChains/MSVC.cpp b/clang/lib/Driver/ToolChains/MSVC.cpp
index 6f5f541..9e9d943 100644
--- a/clang/lib/Driver/ToolChains/MSVC.cpp
+++ b/clang/lib/Driver/ToolChains/MSVC.cpp
@@ -529,9 +529,7 @@
   SkipSettingEnvironment:;
 #endif
   } else {
-    linkPath = Linker;
-    llvm::sys::path::replace_extension(linkPath, "exe");
-    linkPath = TC.GetProgramPath(linkPath.c_str());
+    linkPath = TC.GetProgramPath(Linker.str().c_str());
   }
 
   auto LinkCmd = llvm::make_unique<Command>(