Do not GVN HLocalGet. If the local is final, the GVN thinks it can loop hoist accesses to it (which…

lib/compiler/implementation/ssa/nodes.dart

Index: lib/compiler/implementation/ssa/nodes.dart
===================================================================
--- lib/compiler/implementation/ssa/nodes.dart	(revision 13220)
+++ lib/compiler/implementation/ssa/nodes.dart	(working copy)
@@ -1557,6 +1557,12 @@
   accept(HVisitor visitor) => visitor.visitLocalGet(this);
 
   HLocalValue get local => inputs[0];
+
+  void prepareGvn(HTypeMap types) {
+    // No need to use GVN for a [HLocalGet], it is just a local
+    // access.
+    clearAllSideEffects();
+  }
 }
 
 class HLocalSet extends HFieldSet {