Deserialize ResolvedAsts and ResolutionImpacts only when needed for compilation.

tests/compiler/dart2js/serialization/reserialization_test.dart

Index: tests/compiler/dart2js/serialization/reserialization_test.dart
diff --git a/tests/compiler/dart2js/serialization/reserialization_test.dart b/tests/compiler/dart2js/serialization/reserialization_test.dart
index 691bdab44127e6ee1f598bd2756c3123cc4906fb..2f56e2e735c07e4471cd0fd41d53f23ae4c769d4 100644
--- a/tests/compiler/dart2js/serialization/reserialization_test.dart
+++ b/tests/compiler/dart2js/serialization/reserialization_test.dart
@@ -38,14 +38,16 @@ Future testReserialization(Uri entryPoint) async {
 
   SerializationResult result2 = await serialize(entryPoint,
       memorySourceFiles: serializedData1.toMemorySourceFiles(),
-      resolutionInputs: serializedData1.toUris());
+      resolutionInputs: serializedData1.toUris(),
+      deserializeCompilationDataForTesting: true);
   Compiler compiler2 = result2.compiler;
   SerializedData serializedData2 = result2.serializedData;
   Iterable<LibraryElement> libraries2 = compiler2.libraryLoader.libraries;
 
   SerializationResult result3 = await serialize(entryPoint,
       memorySourceFiles: serializedData2.toMemorySourceFiles(),
-      resolutionInputs: serializedData2.toUris());
+      resolutionInputs: serializedData2.toUris(),
+      deserializeCompilationDataForTesting: true);
   Compiler compiler3 = result3.compiler;
   Iterable<LibraryElement> libraries3 = compiler3.libraryLoader.libraries;