chore: do not compile AnyVal for now (#23189)

dotty is not able to compile `scala.AnyVal` from source. We ignore the
source file of `scala.AnyVal` for now.
~We also partially revert #23527 to enable back a disabled test because
of the reason mentioned before.~


EDIT: enabling the test back requires to fix the issue with `-Ycheck`,
(which cannot be fixed before 3.8.0? at least not fully)

Author: hamzaremmal