Fix GH-8080: ReflectionClass::getConstants() depends on def. order

When we need to evaluate constant ASTs, we always have to do that in
the scope where the constant has been defined, whi

Fix GH-8080: ReflectionClass::getConstants() depends on def. order

When we need to evaluate constant ASTs, we always have to do that in
the scope where the constant has been defined, which may be a parent
of the `ReflectionClass`'s scope.

Closes GH-8106.

show more ...