Add support for class Name Resolution As Scalar Via "class" Keyword

[thekid]

See https://wiki.php.net/rfc/class_name_scalars. Added to PHP syntax, supported in both code and annotations:

#[@test, @expect(IllegalArgumentException::class)]
public function raises_an_exception() {
  // ...
}

#[@test]
public function is_instance_of_type() {
  $this->assertInstanceOf(Type::class, $this->fixture);
}