VM: Remove unnecessary field use_kind from IL instructions.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
===================================================================
--- runtime/vm/intermediate_language.cc	(revision 36349)
+++ runtime/vm/intermediate_language.cc	(working copy)
@@ -43,7 +43,6 @@
       ssa_temp_index_(-1),
       input_use_list_(NULL),
       env_use_list_(NULL),
-      use_kind_(kValue),  // Phis and parameters rely on this default.
       constant_value_(Object::ZoneHandle(ConstantPropagator::Unknown())) {
 }
 
@@ -1403,7 +1402,7 @@
         new MathUnaryInstr(MathUnaryInstr::kDoubleSquare,
                            new Value(left()->definition()),
                            DeoptimizationTarget());
-    flow_graph->InsertBefore(this, math_unary, env(), Definition::kValue);
+    flow_graph->InsertBefore(this, math_unary, env(), FlowGraph::kValue);
     return math_unary;
   }
 
@@ -1661,7 +1660,7 @@
   ConstantInstr* c = value()->definition()->AsConstant();
   if ((c != NULL) && c->value().IsDouble()) {
     UnboxedConstantInstr* uc = new UnboxedConstantInstr(c->value());
-    flow_graph->InsertBefore(this, uc, NULL, Definition::kValue);
+    flow_graph->InsertBefore(this, uc, NULL, FlowGraph::kValue);
     return uc;
   }