Add generic types to Sort and Comparable. Fix crasher bug in codegen.

tool/input_sdk/lib/core/comparable.dart

Index: tool/input_sdk/lib/core/comparable.dart
diff --git a/tool/input_sdk/lib/core/comparable.dart b/tool/input_sdk/lib/core/comparable.dart
index 7a22948a080fabb5649088b32bcfc4499fcb89c2..0609301eaa9e726f44a78c68ee844a5fb57c56fe 100644
--- a/tool/input_sdk/lib/core/comparable.dart
+++ b/tool/input_sdk/lib/core/comparable.dart
@@ -90,5 +90,5 @@ abstract class Comparable<T> {
    * This utility function is used as the default comparator
    * for ordering collections, for example in the [List] sort function.
    */
-  static int compare(Comparable a, Comparable b) => a.compareTo(b);
+  static int compare/*<E>*/(Comparable/*<E>*/ a, dynamic /*=E*/ b) => a.compareTo(b);
 }