Fix computation of relative paths in depsfile when cross-compiling

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
index 8c9894004dedccfd571da4b82196e44757182715..a6fdbf60c2c79dcac13e77a3c0a7d1dc3b39c75a 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
@@ -285,9 +285,8 @@ class KernelTarget extends TargetImplementation {
 
   Future writeDepsFile(Uri output, Uri depsFile,
       {Iterable<Uri> extraDependencies}) async {
-    Uri base = depsFile.resolve(".");
     String toRelativeFilePath(Uri uri) {
-      return Uri.parse(relativizeUri(uri, base: base)).toFilePath();
+      return Uri.parse(relativizeUri(uri)).toFilePath();
     }
 
     if (loader.first == null) return null;