Ensure that when import/export are used natively in the JS runtime that the check for alias symbol is re-applied - re comment in microsoft#26912

Author: orta

src/compiler/checker.ts

@@ -30004,7 +30004,7 @@ namespace ts {
         function checkImportBinding(node: ImportEqualsDeclaration | ImportClause | NamespaceImport | ImportSpecifier) {
             checkCollisionWithRequireExportsInGeneratedCode(node, node.name!);
             checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name!);
-            if (!isInJSFile(node)) {
+            if (!isInJSFile(node) || languageVersion < ScriptTarget.ES2020) {
                 checkAliasSymbol(node);
             }
         }