fix(43535): preserves 'override' modifier in JavaScript output (#43536)

tests/cases/conformance/override/override12.ts

@@ -0,0 +1,26 @@
+// @noImplicitOverride: true
+// @target: es2015,esnext
+
+class A {
+    public m1(): number {
+        return 0;
+    }
+
+    public m2(): number {
+        return 0;
+    }
+
+    public m3(): void {}
+}
+
+class B extends A {
+    override m1() {
+        return 10;
+    }
+
+    override m2(): number {
+        return 30;
+    }
+
+    override m3(): void {}
+}