Implemented support for generalized void in analyzer.

tests/language/generalized_void_syntax_test.dart

 // Copyright (c) 2017, 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.
 
-// Testing that the reserved word `void` is allowed to occur as a type.
-
-import 'package:expect/expect.dart';
+// Testing that the reserved word `void` is allowed to occur as a type, not
+// just as a return type.
 
 class A<T> {
-  T t;
+  final T t;
   const A(this.t);
 }
 
 const void x1 = null;
 const A<void> x2 = const A<void>(null);
 
 final void x3 = null;
 final A<void> x4 = new A<void>(null);
 
 void x5 = null, x6;
 A<void> x7 = new A<void>(null), x8;
 
 void get g1 => null;
 A<void> get g2 => new A<void>(null);
 void set s1(void x) => null;
 void set s2(A<void> x) => null;
 void m1(void x, [void y]) => null;
 void m2(void x, {void y}) => null;
 A<void> m3(A<void> x, [A<void> y]) => new A<void>(null);
 A<void> m4(A<void> x, {A<void> y}) => new A<void>(null);
 
-class B<S, T> {}
+class B<S, T> implements A<void> { void get t => null; }
 
-class C extends A<void> with B<void, A<void>> implements A<void> {
+class C extends A<void> with B<void, A<void>> {
+  C(): super(null);
+  
   static final void x1 = null;
   static final A<void> x2 = new A<void>(null);
 
   static const void x3 = null;
   static const A<void> x4 = const A<void>(null);
 
-  final void x5 = null, x6;
-  final A<void> x7 = new A<void>(null), x8;
+  final void x5 = null;
+  final A<void> x6 = new A<void>(null);
 
-  static void x9 = null, x10;
-  static A<void> x11 = new A<void>(null), x12;
+  static void x7 = null, x8;
+  static A<void> x9 = new A<void>(null), x10;
 
-  covariant void x13 = null, x14;
-  covariant A<void> x15 = new A<void>(null), x16;
+  covariant void x11 = null, x12;
+  covariant A<void> x13 = new A<void>(null), x14;
   
   static void get g1 => null;
   static A<void> get g2 => new A<void>(null);
   static void set s1(void x) => null;
   static void set s2(A<void> x) => null;
   static void m1(void x, [void y]) => null;
   static void m2(void x, {void y}) => null;
   static A<void> m3(A<void> x, [A<void> y]) => null;
   static A<void> m4(A<void> x, {A<void> y}) => null;
 
   void get g3 => null;
   A<void> get g4 => new A<void>(null);
   void set s3(void x) => null;
   void set s4(A<void> x) => null;
   void m5(void x, [void y]) => null;
   void m6(void x, {void y}) => null;
   A<void> m7(A<void> x, [A<void> y]) => null;
   A<void> m8(A<void> x, {A<void> y}) => null;
 
   // Ensure that all members are used, and use `void` in expressions.
   void run() {
-    var ignore = [x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14,
-      x15, x16, g1, g2, g3, g4];
+    var ignore = [
+      x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, //
+      g1, g2, g3, g4,
+    ];
     
     s1 = null;
     s2 = new A<void>(null);
     s3 = null;
     s4 = new A<void>(null);
     m1(null, null);
     m2(null, y: null);
     m3(null, new A<void>(null));
     m4(null, y: new A<void>(null));
     m5(null, null);
@@ skipping 14 matching lines @@
   var ignore = [x1, x2, x3, x4, x5, x6, x7, x8, g1, g2];
 
   s1 = null;
   s2 = new A<void>(null);
   m1(null, null);
   m2(null, y: null);
   m3(null, null);
   m4(null, y: null);
   new C().run();
 }