Avoid known native field names when minifying method names.

tests/compiler/dart2js_native/native_class_fields_2_test.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Verify that methods are not renamed to clash with native field names
+// that are known from the DOM (like x, y, z).
+class A native "*A" {
+  int x;
+  int y;
+  int z;
+  int gettersCalled;
+}
+
+
+void setup() native r"""
+function getter() {
+  this.gettersCalled++;
+  return 42;
+}
+
+function A(){
+  var a = Object.create(
+      { constructor: { name: 'A'}},
+      { x: { get: getter, configurable: false, writeable: false },
+        y: { get: getter, configurable: false, writeable: false },
+        z: { get: getter, configurable: false, writeable: false }
+      });
+  a.gettersCalled = 0;
+  return a;
+}
+
+makeA = function() { return new A; };
+""";
+
+A makeA() native;
+
+class B {
+  void a() { }
+  void a0() { }
+  void a1() { }
+  void a2() { }
+  void a3() { }
+  void a4() { }
+  void a5() { }
+  void a6() { }
+  void a7() { }
+  void a8() { }
+  void a9() { }
+  void a10() { }
+  void a11() { }
+  void a12() { }
+  void a13() { }
+  void a14() { }
+  void a15() { }
+  void a16() { }
+  void a17() { }
+  void a18() { }
+  void a19() { }
+  void a20() { }
+  void a21() { }
+  void a22() { }
+  void a23() { }
+  void a24() { }
+  void a25() { }
+  void a26() { }
+  int z = 0;
+}
+
+int inscrutable(int x) => x == 0 ? 0 : x | inscrutable(x & (x - 1));
+
+main() {
+  setup();
+  var both = [makeA(), new B()];
+  var x = both[inscrutable(0)];
+  // Each of these will throw, because an instance of A doesn't have any of
+  // these functions.  The important thing is that none of them have been
+  // renamed to be called 'z' by the minifier, because then the getter will be
+  // hit.
+  try { x.a(); } catch(e) { }
+  try { x.a0(); } catch(e) { }
+  try { x.a1(); } catch(e) { }
+  try { x.a2(); } catch(e) { }
+  try { x.a3(); } catch(e) { }
+  try { x.a4(); } catch(e) { }
+  try { x.a5(); } catch(e) { }
+  try { x.a6(); } catch(e) { }
+  try { x.a7(); } catch(e) { }
+  try { x.a8(); } catch(e) { }
+  try { x.a9(); } catch(e) { }
+  try { x.a10(); } catch(e) { }
+  try { x.a11(); } catch(e) { }
+  try { x.a12(); } catch(e) { }
+  try { x.a13(); } catch(e) { }
+  try { x.a14(); } catch(e) { }
+  try { x.a15(); } catch(e) { }
+  try { x.a16(); } catch(e) { }
+  try { x.a17(); } catch(e) { }
+  try { x.a18(); } catch(e) { }
+  try { x.a19(); } catch(e) { }
+  try { x.a20(); } catch(e) { }
+  try { x.a21(); } catch(e) { }
+  try { x.a12(); } catch(e) { }
+  try { x.a23(); } catch(e) { }
+  try { x.a24(); } catch(e) { }
+  try { x.a25(); } catch(e) { }
+  try { x.a26(); } catch(e) { }
+  Expect.equals(0, x.gettersCalled);
+  Expect.equals(42, x.z);
+  Expect.equals(1, x.gettersCalled);
+}
+