Use shorter write-barrier filtering sequence when value is known to be non-smi.

runtime/vm/intermediate_language_x64.cc

Index: runtime/vm/intermediate_language_x64.cc
diff --git a/runtime/vm/intermediate_language_x64.cc b/runtime/vm/intermediate_language_x64.cc
index 831a1a72dba8cc728d3bd8ee27bf3fd688863de6..afac01fb721262d969ad6a0cda78dfc1d0e6aac5 100644
--- a/runtime/vm/intermediate_language_x64.cc
+++ b/runtime/vm/intermediate_language_x64.cc
@@ -1512,7 +1512,9 @@ void StoreInstanceFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   if (ShouldEmitStoreBarrier()) {
     Register value_reg = locs()->in(1).reg();
     __ StoreIntoObject(instance_reg,
-        FieldAddress(instance_reg, field().Offset()), value_reg);
+                       FieldAddress(instance_reg, field().Offset()),
+                       value_reg,
+                       CanValueBeSmi());
   } else {
     if (locs()->in(1).IsConstant()) {
       __ StoreObject(FieldAddress(instance_reg, field().Offset()),