In order of preference, the generated name will be:
new class extends ParentClass {};
// -> ParentClass@anonymous
new class implements FirstInterface, SecondInterface {};
// -> FirstInterface@anonymous
new class {};
// -> class@anonymous
This is intended to display a more useful class name in error messages
and stack traces, and thus make debugging easier.
Closes GH-5153.
Do not include unbound anonymous classes in get_declared_classes().
Note that earlier PHP versions would include the anonymous class in
get_declared_classes(), and return false until the class was bound,
but would not crash.
