Sort procedures by source positions.

pkg/front_end/lib/src/fasta/source/source_class_builder.dart

Index: pkg/front_end/lib/src/fasta/source/source_class_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
index 8990bb28868022aed31568c432513e14ca144dae..f2e38c9337c213a6c88ae1f235bcaddfabd47883 100644
--- a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
@@ -22,7 +22,8 @@ import '../kernel/kernel_builder.dart'
         LibraryBuilder,
         MetadataBuilder,
         ProcedureBuilder,
-        TypeVariableBuilder;
+        TypeVariableBuilder,
+        compareProcedures;
 
 import '../dill/dill_member_builder.dart' show DillMemberBuilder;
 
@@ -113,6 +114,8 @@ class SourceClassBuilder extends KernelClassBuilder {
         }
       }
     }
+
+    cls.procedures.sort(compareProcedures);
     return cls;
   }