Fix test that used raw string literals. Doesn't work in C++03

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@361894 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/re/re.regex/re.regex.construct/bad_range.pass.cpp

@@ -31,8 +31,8 @@ static bool error_range_thrown(const char *pat)
 
 int main(int, char**)
 {
-    assert(error_range_thrown(R"([\w-a])"));
-    assert(error_range_thrown(R"([a-\w])"));
+    assert(error_range_thrown("([\\w-a])"));
+    assert(error_range_thrown("([a-\\w])"));
 
   return 0;
 }