refactor(compiler): ensure compatibility with typescript strict flag (#30993)

As part of FW-1265, the `@angular/compiler` package is made compatible
with the TypeScript `--strict` flag. This already unveiled a few bugs,
so the strictness flag seems to help with increasing the overall code health.

Read more about the strict flag [here](https://www.typescriptlang.org/docs/handbook/compiler-options.html)

PR Close #30993

packages/compiler/src/ml_parser/ast.ts

@@ -112,7 +112,7 @@ export class RecursiveVisitor implements Visitor {
       if (children) results.push(visitAll(t, children, context));
     }
     cb(visit);
-    return [].concat.apply([], results);
+    return Array.prototype.concat.apply([], results);
   }
 }
 
@@ -149,4 +149,4 @@ export function findNode(nodes: Node[], position: number): HtmlAstPath {
   visitAll(visitor, nodes);
 
   return new AstPath<Node>(path, position);
-}
+}