Raw string d-char-sequence isn't supported

The test consists of several raw string literals like:
char s_1[] = R"$(\u0041\U00000061\t\v\n\r\000 /09:@!#$%&'(*+,-./:;<=>?`

~])$";

The parser issues an error because $ isn't a legal character. The C++14 standard actual allows any sequence of characters between the " and (.