Sort procedures by source positions.

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

Index: pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
index d7486c99a62baddc322c194bf65f3be9abcc176f..c393515d9ce5a05d294a117bcaa70f8aebb751e7 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
@@ -106,3 +106,9 @@ dynamic memberError(Member member, Object error, [int charOffset]) {
   name = (cls == null ? "" : "${cls.name}::") + name;
   return inputError(uri, charOffset, "Error in $name: $error");
 }
+
+int compareProcedures(Procedure a, Procedure b) {
+  int i = a.fileUri.compareTo(b.fileUri);
+  if (i != 0) return i;
+  return a.fileOffset.compareTo(b.fileOffset);
+}