Revert r157819, "#ifdef out a broken test on win32"

FYI, LLVM_ON_WIN32 is useless.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@157890 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Tooling/ToolingTest.cpp b/unittests/Tooling/ToolingTest.cpp
index efabaf7..9122786 100644
--- a/unittests/Tooling/ToolingTest.cpp
+++ b/unittests/Tooling/ToolingTest.cpp
@@ -110,9 +110,6 @@
   EXPECT_TRUE(Action.get() != NULL);
 }
 
-#ifndef LLVM_ON_WIN32
-// This test breaks on Windows.
-
 TEST(ToolInvocation, TestMapVirtualFile) {
   clang::FileManager Files((clang::FileSystemOptions()));
   std::vector<std::string> Args;
@@ -126,7 +123,5 @@
   EXPECT_TRUE(Invocation.run());
 }
 
-#endif
-
 } // end namespace tooling
 } // end namespace clang