Add a way to use shared CanonicalName root to deserialize Program.

pkg/front_end/test/fasta/testing/suite.dart

Index: pkg/front_end/test/fasta/testing/suite.dart
diff --git a/pkg/front_end/test/fasta/testing/suite.dart b/pkg/front_end/test/fasta/testing/suite.dart
index f08f6cded4ebb3aca14f163ddcfd4558a486eded..69b1cffd7c26cae83ec1f27fca38e91600b67ef8 100644
--- a/pkg/front_end/test/fasta/testing/suite.dart
+++ b/pkg/front_end/test/fasta/testing/suite.dart
@@ -192,7 +192,8 @@ class Outline extends Step<TestDescription, Program, FastaContext> {
       TestDescription description, FastaContext context) async {
     Program platform = await context.loadPlatform();
     Ticker ticker = new Ticker();
-    DillTarget dillTarget = new DillTarget(ticker, context.uriTranslator);
+    DillTarget dillTarget = new DillTarget(null, ticker, context.uriTranslator);
+    platform.unbindCanonicalNames();
     dillTarget.loader.appendLibraries(platform);
     KernelTarget sourceTarget = astKind == AstKind.Analyzer
         ? new AnalyzerTarget(dillTarget, context.uriTranslator, strongMode)