Test closed world model after deserialization.

pkg/compiler/lib/src/compiler.dart

Index: pkg/compiler/lib/src/compiler.dart
diff --git a/pkg/compiler/lib/src/compiler.dart b/pkg/compiler/lib/src/compiler.dart
index 5665810615b69edba2091eeb2c78519b4852cab7..c807148d52077a417df0f09a7da6412040c33173 100644
--- a/pkg/compiler/lib/src/compiler.dart
+++ b/pkg/compiler/lib/src/compiler.dart
@@ -1960,7 +1960,7 @@ class _CompilerResolution implements Resolution {
   final Map<Element, ResolutionImpact> _resolutionImpactCache =
       <Element, ResolutionImpact>{};
   final Map<Element, WorldImpact> _worldImpactCache = <Element, WorldImpact>{};
-  bool retainCaches = false;
+  bool retainCachesForTesting = false;
 
   _CompilerResolution(this.compiler);
 
@@ -2032,7 +2032,7 @@ class _CompilerResolution implements Resolution {
       assert(invariant(element, !element.isSynthesized || tree == null));
       ResolutionImpact resolutionImpact =
           compiler.resolver.resolve(element);
-      if (compiler.serialization.supportSerialization || retainCaches) {
+      if (compiler.serialization.supportSerialization || retainCachesForTesting) {
         // [ResolutionImpact] is currently only used by serialization. The
         // enqueuer uses the [WorldImpact] which is always cached.
         // TODO(johnniwinther): Align these use cases better; maybe only
@@ -2055,7 +2055,7 @@ class _CompilerResolution implements Resolution {
 
   @override
   void uncacheWorldImpact(Element element) {
-    if (retainCaches) return;
+    if (retainCachesForTesting) return;
     if (compiler.serialization.isDeserialized(element)) return;
     assert(invariant(element, _worldImpactCache[element] != null,
         message: "WorldImpact not computed for $element."));
@@ -2065,7 +2065,7 @@ class _CompilerResolution implements Resolution {
 
   @override
   void emptyCache() {
-    if (retainCaches) return;
+    if (retainCachesForTesting) return;
     for (Element element in _worldImpactCache.keys) {
       _worldImpactCache[element] = const WorldImpact();
     }