Remove hack now issue has been fixed (#2773)

diff --git a/test/descriptor/git.dart b/test/descriptor/git.dart
index 53101f9..bf3c0fa 100644
--- a/test/descriptor/git.dart
+++ b/test/descriptor/git.dart
@@ -4,7 +4,6 @@
 
 import 'dart:async';
 
-import 'dart:io';
 import 'package:path/path.dart' as path;
 import 'package:pub/src/git.dart' as git;
 import 'package:test_descriptor/test_descriptor.dart';
@@ -21,9 +20,9 @@
     await _runGitCommands(parent, [
       ['init'],
       [
-        'config', 'core.excludesfile',
-        // TODO(sigurdm): This works around https://github.com/dart-lang/sdk/issues/40060
-        Platform.isWindows ? '""' : ''
+        'config',
+        'core.excludesfile',
+        '',
       ],
       ['add', '.'],
       ['commit', '-m', 'initial commit', '--allow-empty']