enable lint avoid_relative_lib_imports (#15780)

packages/flutter_tools/bin/fuchsia_tester.dart

diff --git a/packages/flutter_tools/bin/fuchsia_tester.dart b/packages/flutter_tools/bin/fuchsia_tester.dart
index 3c71166..b78ff45 100644
--- a/packages/flutter_tools/bin/fuchsia_tester.dart
+++ b/packages/flutter_tools/bin/fuchsia_tester.dart
@@ -5,24 +5,24 @@
 import 'dart:async';
 
 import 'package:args/args.dart';
+import 'package:flutter_tools/src/base/common.dart';
+import 'package:flutter_tools/src/base/config.dart';
+import 'package:flutter_tools/src/base/context.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/base/io.dart';
+import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/base/os.dart';
+import 'package:flutter_tools/src/base/platform.dart';
+import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/dart/package_map.dart';
+import 'package:flutter_tools/src/disabled_usage.dart';
+import 'package:flutter_tools/src/globals.dart';
+import 'package:flutter_tools/src/test/flutter_platform.dart' as loader;
+import 'package:flutter_tools/src/usage.dart';
 import 'package:process/process.dart';
 import 'package:test/src/executable.dart'
     as test; // ignore: implementation_imports
 
-import '../lib/src/base/common.dart';
-import '../lib/src/base/config.dart';
-import '../lib/src/base/context.dart';
-import '../lib/src/base/file_system.dart';
-import '../lib/src/base/io.dart';
-import '../lib/src/base/logger.dart';
-import '../lib/src/base/os.dart';
-import '../lib/src/base/platform.dart';
-import '../lib/src/cache.dart';
-import '../lib/src/dart/package_map.dart';
-import '../lib/src/disabled_usage.dart';
-import '../lib/src/globals.dart';
-import '../lib/src/test/flutter_platform.dart' as loader;
-import '../lib/src/usage.dart';
 
 // Note: this was largely inspired by lib/src/commands/test.dart.