Fix quote lang cache regression

Fixes RT#132262: https://rt.perl.org/Ticket/Display.html?id=132262

After the Big Slang Refactor, the quote lang cache started to fail
to notice when the cached lang was mutated (e.g. by defining
a new prefix op). This caused failure to parse new ops, such
as behaviour in the ticket, since the new quoted block still used the
old pre-op-mixin lang.

Fix by adding the name of the lang object to key the cache on.

src/Perl6/Grammar.nqp

@@ -65,7 +65,9 @@ role STD {
     method quote_lang($l, $start, $stop, @base_tweaks?, @extra_tweaks?) {
         sub lang_key() {
             my $stopstr := nqp::istype($stop,VMArray) ?? nqp::join(' ',$stop) !! $stop;
-            my @keybits := [$l.HOW.name($l), $start, $stopstr];
+            my @keybits := [
+                self.HOW.name(self), $l.HOW.name($l), $start, $stopstr
+            ];
             for @base_tweaks {
                 @keybits.push($_);
             }