JS: prevent Any.equals from mangling

js/js.translator/testData/box/native/equalsMangling.js

@@ -0,0 +1,10 @@
+function foo(first, second) {
+    return first.equals(second);
+}
+
+function B(value) {
+    this.value = value;
+}
+B.prototype.equals = function(other) {
+    return other instanceof B && other.value == this.value;
+};