Remove fallback mode and corresponding cli flag.

pkg/analyzer_cli/test/options_test.dart

 // Copyright (c) 2015, 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 analyzer_cli.test.options;
 
 import 'dart:io';
 
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/options.dart';
 import 'package:args/args.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 main() {
   group('CommandLineOptions', () {
     group('parse', () {
       test('defaults', () {
         CommandLineOptions options =
             CommandLineOptions.parse(['--dart-sdk', '.', 'foo.dart']);
         expect(options, isNotNull);
         expect(options.buildMode, isFalse);
         expect(options.buildAnalysisOutput, isNull);
-        expect(options.buildSummaryFallback, isFalse);
         expect(options.buildSummaryInputs, isEmpty);
         expect(options.buildSummaryOnly, isFalse);
         expect(options.buildSummaryOutput, isNull);
         expect(options.buildSummaryOutputSemantic, isNull);
         expect(options.buildSuppressExitCode, isFalse);
         expect(options.dartSdkPath, isNotNull);
         expect(options.disableHints, isFalse);
         expect(options.lints, isFalse);
         expect(options.displayVersion, isFalse);
         expect(options.enableStrictCallChecks, isFalse);
@@ skipping 222 matching lines @@
     _parse(['--build-mode', 'package:p/foo.dart|/path/to/p/lib/foo.dart']);
     expect(options.buildMode, isTrue);
   }
 
   test_buildMode_allowsEmptyFileList() {
     _parse(['--build-mode']);
     expect(options.buildMode, isTrue);
     expect(options.sourceFiles, isEmpty);
   }
 
-  test_buildSummaryFallback() {
-    _parse([
-      '--build-mode',
-      '--build-summary-output=//path/to/output.sum',
-      '--build-summary-fallback',
-      'package:p/foo.dart|/path/to/p/lib/foo.dart'
-    ]);
-    expect(options.buildMode, isTrue);
-    expect(options.buildSummaryFallback, isTrue);
-  }
-
   test_buildSummaryInputs_commaSeparated() {
     _parse([
       '--build-mode',
       '--build-summary-input=/path/to/aaa.sum,/path/to/bbb.sum',
       'package:p/foo.dart|/path/to/p/lib/foo.dart'
     ]);
     expect(options.buildMode, isTrue);
     expect(
         options.buildSummaryInputs, ['/path/to/aaa.sum', '/path/to/bbb.sum']);
   }
@@ skipping 69 matching lines @@
       'package:p/foo.dart|/path/to/p/lib/foo.dart'
     ]);
     expect(options.buildMode, isTrue);
     expect(options.buildSuppressExitCode, isTrue);
   }
 
   void _parse(List<String> args) {
     options = CommandLineOptions.parse(args);
   }
 }