update DDC and analyzer cli preprocessArgs

pkg/analyzer/test/src/command_line/arguments_test.dart

 // Copyright (c) 2016, 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.test.src.context.context_builder_test;
 
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/command_line/arguments.dart';
 import 'package:analyzer/src/context/builder.dart';
 import 'package:analyzer/src/dart/sdk/sdk.dart';
@@ skipping 148 matching lines @@
     List<String> args = ['--xx', '--yy=abc', 'foo', 'bar'];
     ArgResults result = parse(provider, parser, args);
     expect(result, isNotNull);
     expect(result['xx'], true);
     expect(result['yy'], 'abc');
     expect(result.rest, orderedEquals(['foo', 'bar']));
   }
 
   void test_preprocessArgs_noReplacement() {
     MemoryResourceProvider provider = new MemoryResourceProvider();
-    List<String> result = preprocessArgs(provider, ['--xx' '--yy' 'baz']);
-    expect(result, orderedEquals(['--xx' '--yy' 'baz']));
+    List<String> original = ['--xx' '--yy' 'baz'];
+    List<String> result = preprocessArgs(provider, original);
+    expect(result, orderedEquals(original));
+    expect(identical(original, result), isFalse);
   }
 
   void test_preprocessArgs_replacement_exists() {
     MemoryResourceProvider provider = new MemoryResourceProvider();
     String filePath = provider.convertPath('/args.txt');
     provider.newFile(
         filePath,
         '''
 -a
 --xx
 
 foo
 bar
 ''');
     List<String> result =
         preprocessArgs(provider, ['--preserved', '@$filePath']);
     expect(result, orderedEquals(['--preserved', '-a', '--xx', 'foo', 'bar']));
   }
 
   void test_preprocessArgs_replacement_nonexistent() {
     MemoryResourceProvider provider = new MemoryResourceProvider();
     String filePath = provider.convertPath('/args.txt');
     List<String> args = ['ignored', '@$filePath'];
-    List<String> result = preprocessArgs(provider, args);
-    expect(result, orderedEquals(args));
+    try {
+      preprocessArgs(provider, args);
+      fail('Expect exception');
+    } on Exception catch (e) {
+      expect(e.toString(), contains('Failed to read file'));
+      expect(e.toString(), contains('@$filePath'));
+    }
   }
 
   void test_preprocessArgs_replacement_notLast() {
     MemoryResourceProvider provider = new MemoryResourceProvider();
     String filePath = provider.convertPath('/args.txt');
     List<String> args = ['a', '@$filePath', 'b'];
     List<String> result = preprocessArgs(provider, args);
     expect(result, orderedEquals(args));
   }
 }