Remove unused imports

Change-Id: Ieceb2f150a8f579231bda40c92215e61adc69f7a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/114922
Reviewed-by: Mike Fairhurst <mfairhurst@google.com>
Commit-Queue: Mike Fairhurst <mfairhurst@google.com>

Author: MichaelRFairhurst

pkg/analyzer/lib/src/task/strong/checker.dart

@@ -8,7 +8,6 @@ import 'dart:collection';
 
 import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/ast/token.dart' show TokenType;
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';

pkg/analyzer/test/generated/resolver_test_case.dart

@@ -7,7 +7,6 @@ import 'dart:async';
 import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';

pkg/analyzer/test/utils.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/generated/resolver.dart' show TypeProvider;