Call operator shared test and parser updates for operator call in dartc.

tests/language/src/CallOperatorTest.dart

+// Copyright (c) 2012, 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.
+
+
+// simple test with no types in signature
+class A1 {
+  operator call() => 42;
+}
+
+// same test, include return type
+class A2 {
+  int operator call() => 35;
+}
+
+class B {
+  call() => 28; // expect warning, should use 'operator call'
+}
+
+// A call() operator can have any arity
+class C {
+  operator call(arg) => 7 * arg;
+}
+
+// Test named arguments
+class D {
+  operator call([arg=6]) => 7 * arg;
+}
+
+// non-trvial method body combination of positional and named
+class E {
+  String operator call(String str, [int count=1]) {
+    String result = "";
+    for (var i = 0; i < count; i++) {
+      result += str;
+      if (i < count -1) {
+        result += ':';
+      }
+    }
+    return result;
+  }
+}
+
+main() {
+  var a1 = new A1();
+  Expect.equals(42, a1());
+  Expect.equals(42, a1.call());
+
+  var a2 = new A2();
+  Expect.equals(35, a2());
+  Expect.equals(35, a2.call());
+
+  var b = new B();
+  Expect.equals(28, b());
+  Expect.equals(28, b.call());
+
+  var c = new C();
+  Expect.equals(42, c(6));
+  Expect.equals(42, c.call(6));
+
+  var d = new D();
+  Expect.equals(42, d());
+  Expect.equals(7, d(1));
+  Expect.equals(14, d(arg:2));
+  Expect.equals(42, d.call());
+  Expect.equals(7, d.call(1));
+  Expect.equals(14, d.call(arg:2));
+
+  var e = new E();
+  Expect.equals("foo", e("foo"));
+  Expect.equals("foo:foo", e("foo", 2));
+  Expect.equals("foo:foo:foo", e("foo", count:3));
+  Expect.equals("foo", e.call("foo"));
+  Expect.equals("foo:foo", e.call("foo", 2));
+  Expect.equals("foo:foo:foo", e.call("foo", count:3));
+}