Ensure locations are always provided, but don't store them yet.

pkg/front_end/test/subpackage_relationships_test.dart

Index: pkg/front_end/test/subpackage_relationships_test.dart
diff --git a/pkg/front_end/test/subpackage_relationships_test.dart b/pkg/front_end/test/subpackage_relationships_test.dart
index f1319225f62c56ab8ab71b985506e1d2c270a8f3..df138c0e70272994749f6e24bff7f7d6ee0c6bb8 100644
--- a/pkg/front_end/test/subpackage_relationships_test.dart
+++ b/pkg/front_end/test/subpackage_relationships_test.dart
@@ -39,6 +39,7 @@ final subpackageRules = {
     'lib/src/fasta/parser',
     'lib/src/fasta/scanner',
     'lib/src/fasta/testing',
+    'lib/src/fasta/util',
   ]),
   'lib/src/fasta/analyzer':
       new SubpackageRules(mayImportAnalyzer: true, allowedDependencies: [
@@ -69,6 +70,7 @@ final subpackageRules = {
     'lib/src/fasta/parser',
     'lib/src/fasta/scanner',
     'lib/src/fasta/source',
+    'lib/src/fasta/util',
   ]),
   'lib/src/fasta/parser':
       new SubpackageRules(allowSubdirs: true, allowedDependencies: [