Driver: hoist `-fno-rtti-data` to a driver flag

This is needed for building with the GNU driver (`clang++`) when
targeting Windows and using msvcprt.  This flag is the equivalent of
`/GR-`.

llvm-svn: 326469
diff --git a/clang/test/Driver/fno-rtti-data.cpp b/clang/test/Driver/fno-rtti-data.cpp
new file mode 100644
index 0000000..cc2d5b6
--- /dev/null
+++ b/clang/test/Driver/fno-rtti-data.cpp
@@ -0,0 +1,2 @@
+// RUN: %clang -### -fno-rtti-data %s 2>&1 | FileCheck %s
+// CHECK: -fno-rtti-data