Make hashCode a getter and not a method.

lib/compiler/implementation/ssa/value_set.dart

Index: lib/compiler/implementation/ssa/value_set.dart
diff --git a/lib/compiler/implementation/ssa/value_set.dart b/lib/compiler/implementation/ssa/value_set.dart
index bb50d612479711266996077019ed3b8a1abeb6e6..06cadcaf5a211e92486459b12a4e915180ccf6c9 100644
--- a/lib/compiler/implementation/ssa/value_set.dart
+++ b/lib/compiler/implementation/ssa/value_set.dart
@@ -38,7 +38,7 @@ class ValueSet {
     if (probe != null && probe.gvnEquals(instruction)) return probe;
     // Look in the collisions list.
     for (ValueSetNode node = collisions; node != null; node = node.next) {
-      if (node.hashCode() == hashCode) {
+      if (node.hashCode == hashCode) {
         HInstruction cached = node.value;
         if (cached.gvnEquals(instruction)) return cached;
       }
@@ -149,7 +149,7 @@ class ValueSet {
 class ValueSetNode {
   final HInstruction value;
   final int hash;
-  int hashCode() => hash;
+  int get hashCode => hash;
   ValueSetNode next;
   ValueSetNode(this.value, this.hash, this.next);
 }