Fix warnings in dart2js code and re-enable analyzer coverage.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.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.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 2338 matching lines @@
         // For now, native classes cannot be deferred.
         nativeClasses.add(element);
       } else if (isDeferred(element)) {
         deferredClasses.add(element);
       } else {
         regularClasses.add(element);
       }
     }
   }
 
-  int _compareSelectors(Selector selector1, Selector selector2) {
-    int comparison = _compareSelectorNames(selector1, selector2);
-    if (comparison != 0) return comparison;
-
-    Set<ClassElement> classes1 = backend.getInterceptedClassesOn(selector1);
-    Set<ClassElement> classes2 = backend.getInterceptedClassesOn(selector2);
-    if (classes1.length != classes2.length) {
-      return classes1.length - classes2.length;
-    }
-    String getInterceptor1 =
-        namer.getInterceptorName(backend.getInterceptorMethod, classes1);
-    String getInterceptor2 =
-        namer.getInterceptorName(backend.getInterceptorMethod, classes2);
-    return Comparable.compare(getInterceptor1, getInterceptor2);
-  }
-
   // Optimize performance critical one shot interceptors.
   jsAst.Statement tryOptimizeOneShotInterceptor(Selector selector,
                                                 Set<ClassElement> classes) {
     jsAst.Expression isNumber(String variable) {
       return js[variable].typeof.equals(js.string('number'));
     }
 
     jsAst.Expression isNotObject(String variable) {
       return js[variable].typeof.equals(js.string('object')).not;
     }
@@ skipping 396 matching lines @@
 """;
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;