Fix thinko in NFA building, which unbusts 2 out of the 3 failing S05 tests with PIRT.

Author: jnthn

src/QRegex/NFA.nqp

@@ -126,7 +126,8 @@ class QRegex::NFA {
         }
         elsif $subtype ne 'zerowidth' &&
                 ($node.name eq 'alpha' ||
-                    $subtype eq 'method' && (try $node[0][0] eq 'alpha')) {
+                    $subtype eq 'method' &&
+                    ($node[0][0] ~~ QAST::SVal ?? $node[0][0].value !! $node[0][0]) eq 'alpha') {
             $to := self.addedge($from, $to, $EDGE_CHARCLASS + $node.negate,
                 pir::const::CCLASS_ALPHABETIC);
             self.addedge($from, $to, $EDGE_CODEPOINT + $node.negate, 95);