Fix analyzer's handling of import prefixes not followed by '.'.

pkg/analyzer/test/generated/static_warning_code_test.dart

 // Copyright (c) 2014, 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.
 
 library engine.static_warning_code_test;
 
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 3353 matching lines @@
     resolve(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
   void test_undefinedIdentifier_function() {
     Source source = addSource("int a() => b;");
     resolve(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
-  void test_undefinedIdentifier_function_prefix() {
-    addNamedSource("/lib.dart", r'''
-library lib;
-class C {}''');
-    Source source = addSource(r'''
-import 'lib.dart' as b;
-
-int a() => b;
-b.C c;''');
-    resolve(source);
-    assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
-    verify([source]);
-  }
-
   void test_undefinedIdentifier_initializer() {
     Source source = addSource("var a = b;");
     resolve(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
-  void test_undefinedIdentifier_initializer_prefix() {
-    addNamedSource("/lib.dart", r'''
-library lib;
-class C {}''');
-    Source source = addSource(r'''
-import 'lib.dart' as b;
-
-var a = b;
-b.C c;''');
-    resolve(source);
-    assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
-  }
-
   void test_undefinedIdentifier_methodInvocation() {
     Source source = addSource("f() { C.m(); }");
     resolve(source);
     assertErrors(source, [StaticWarningCode.UNDEFINED_IDENTIFIER]);
   }
 
   void test_undefinedIdentifier_private_getter() {
     addNamedSource("/lib.dart", r'''
 library lib;
 class A {
@@ skipping 111 matching lines @@
 
   void test_voidReturnForGetter() {
     Source source = addSource(r'''
 class S {
   void get value {}
 }''');
     resolve(source);
     assertErrors(source, [StaticWarningCode.VOID_RETURN_FOR_GETTER]);
   }
 }