Apply suggestions from code review

Fix compilation.

Co-authored-by: Anders Schack-Mulligen <aschackmull@users.noreply.github.com>

Author: aschackmull

shared/controlflow/codeql/controlflow/AstConsistency.qll

@@ -4,6 +4,7 @@
 overlay[local?]
 module;
 
+private import codeql.util.Location
 private import ControlFlowGraph
 
 module MakeAstConsistency<LocationSig Location, AstSig<Location> Ast> {
@@ -95,7 +96,9 @@ module MakeAstConsistency<LocationSig Location, AstSig<Location> Ast> {
     parent.(PatternMatchExpr).getPattern() = child and member = "PatternMatchExpr.getPattern"
   }
 
-  private class StructuredAstNode extends AstNode {
+  final private class FinalAstNode = AstNode;
+  
+  private class StructuredAstNode extends FinalAstNode {
     StructuredAstNode() {
       this instanceof Callable or
       this instanceof Parameter or