Fix compilation error with gcc 4.8

This version of gcc seems to be having issues with raw literals inside macro
arguments. I change the string to use regular string literals instead.

llvm-svn: 351756

llvm/unittests/ADT/OptionalTest.cpp

@@ -558,10 +558,10 @@ TEST_F(OptionalTest, UseInUnitTests) {
   // Test that we invoke the streaming operators when pretty-printing values in
   // EXPECT macros.
   EXPECT_NONFATAL_FAILURE(EXPECT_EQ(llvm::None, ComparableAndStreamable::get()),
-                          R"(Expected: llvm::None
-      Which is: None
-To be equal to: ComparableAndStreamable::get()
-      Which is: ComparableAndStreamable)");
+                          "Expected: llvm::None\n"
+                          "      Which is: None\n"
+                          "To be equal to: ComparableAndStreamable::get()\n"
+                          "      Which is: ComparableAndStreamable");
 
   // Test that it is still possible to compare objects which do not have a
   // custom streaming operator.