Prevent method calls on nonexistent actions object

[codesections]

NQPMatchRole currently checks if self.actions is null and only looks for and action method if it isn't null. This works for NQP types, but not for Raku types (Grammar, etc) where an unset actions object is Mu (which is non-null). As a result, the current code incorrectly tries to call any methods on Mu with matching names as though they were action methods. This rarely goes well.

This PR adds a check to see if the self.actions does not inherit from Any (that is, is Mu) and skips the method on Mu action objects. (We check for !nqp::istype($actions, Any) instead of nqp::istype(Mu, $actions) because the latter errors for some NQP types).

Fixes rakudo/rakudo#5443

[lizmat]

Closing in lieu of fix in https://github.com/rakudo/rakudo/commit/bd2c719ed4