Remove 'errorCode' field from AnalysisError in the analysis server API.

pkg/analysis_server/test/operation/operation_analysis_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 test.operation.analysis;
 
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/operation/operation_analysis.dart';
 import 'package:analysis_testing/mocks.dart';
 import 'package:analysis_testing/reflective_tests.dart';
@@ skipping 38 matching lines @@
   }
 
   void tearDown() {
     source = null;
     analysisError = null;
   }
 
   void test_noCorrection() {
     Map<String, Object> json = errorToJson(lineInfo, analysisError);
     expect(json, {
-      ERROR_CODE: 'CompileTimeErrorCode.AMBIGUOUS_EXPORT',
       SEVERITY: 'ERROR',
       TYPE: 'COMPILE_TIME_ERROR',
       LOCATION: {
         FILE: 'foo.dart',
         OFFSET: 10,
         LENGTH: 20,
         START_LINE: 3,
         START_COLUMN: 2
       },
       MESSAGE: 'my message'
     });
   }
 
   void test_noLineInfo() {
     Map<String, Object> json = errorToJson(null, analysisError);
     expect(json, {
-      ERROR_CODE: 'CompileTimeErrorCode.AMBIGUOUS_EXPORT',
       SEVERITY: 'ERROR',
       TYPE: 'COMPILE_TIME_ERROR',
       LOCATION: {
         FILE: 'foo.dart',
         OFFSET: 10,
         LENGTH: 20
       },
       MESSAGE: 'my message'
     });
   }
 
   void test_withCorrection() {
     when(analysisError.correction).thenReturn('my correction');
     Map<String, Object> json = errorToJson(lineInfo, analysisError);
     expect(json, {
-      ERROR_CODE: 'CompileTimeErrorCode.AMBIGUOUS_EXPORT',
       SEVERITY: 'ERROR',
       TYPE: 'COMPILE_TIME_ERROR',
       LOCATION: {
         FILE: 'foo.dart',
         OFFSET: 10,
         LENGTH: 20,
         START_LINE: 3,
         START_COLUMN: 2
       },
       MESSAGE: 'my message',
       CORRECTION: 'my correction'
     });
   }
 }