Avoid inlining constants that are used via a deferred import.

sdk/lib/_internal/compiler/implementation/ir/ir_pickler.dart

Index: sdk/lib/_internal/compiler/implementation/ir/ir_pickler.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ir/ir_pickler.dart b/sdk/lib/_internal/compiler/implementation/ir/ir_pickler.dart
index b55ab52d84426c505ee3ce516baa92affc954976..00c9a8ef0a71bc86d9f3c52c87200deb3dcfc033 100644
--- a/sdk/lib/_internal/compiler/implementation/ir/ir_pickler.dart
+++ b/sdk/lib/_internal/compiler/implementation/ir/ir_pickler.dart
@@ -9,7 +9,7 @@ import '../dart2jslib.dart' show
     Constant, FalseConstant, TrueConstant, IntConstant, DoubleConstant,
     StringConstant, NullConstant, ListConstant, MapConstant,
     InterceptorConstant, DummyConstant, FunctionConstant, TypeConstant,
-    ConstructedConstant,
+    ConstructedConstant, DeferredConstant,
     ConstantVisitor, ConstantSystem,
     Compiler, NO_LOCATION_SPANNABLE;
 import 'dart:typed_data' show ByteData, Endianness, Uint8List;
@@ -456,6 +456,7 @@ class ConstantPickler extends ConstantVisitor {
   void visitFunction(FunctionConstant constant) => abort(constant);
   void visitType(TypeConstant constant) => abort(constant);
   void visitConstructed(ConstructedConstant constant) => abort(constant);
+  void visitDeferred(DeferredConstant constant) => abort(constant);
 
   void abort(Constant value) => throw "Can not pickle constant $value";
 }