Remove fromActivation marker from HFieldGet/Set

lib/compiler/implementation/ssa/nodes.dart

Index: lib/compiler/implementation/ssa/nodes.dart
diff --git a/lib/compiler/implementation/ssa/nodes.dart b/lib/compiler/implementation/ssa/nodes.dart
index c5525630131108cd5bea3fcf5d88119f22eadc0d..41b905b748c78e457f7935a613a9145a1d5874f6 100644
--- a/lib/compiler/implementation/ssa/nodes.dart
+++ b/lib/compiler/implementation/ssa/nodes.dart
@@ -1259,8 +1259,6 @@ abstract class HFieldAccess extends HInstruction {
   final Element element;
 
   HFieldAccess(this.element, List<HInstruction> inputs) : super(inputs);
-
-  bool isFromActivation() => element === null;
 }
 
 class HFieldGet extends HFieldAccess {
@@ -1269,7 +1267,6 @@ class HFieldGet extends HFieldAccess {
   HFieldGet(Element element, HInstruction receiver,
             [this.isFinalOrConst = false])
       : super(element, <HInstruction>[receiver]);
-  HFieldGet.fromActivation(receiver) : this(null, receiver);
 
   HInstruction get receiver() => inputs[0];
 
@@ -1288,8 +1285,6 @@ class HFieldGet extends HFieldAccess {
 class HFieldSet extends HFieldAccess {
   HFieldSet(Element element, HInstruction receiver, HInstruction value)
       : super(element, <HInstruction>[receiver, value]);
-  HFieldSet.fromActivation(receiver, value)
-      : this(null, receiver, value);
 
   HInstruction get receiver() => inputs[0];
   HInstruction get value() => inputs[1];