Further improve type optimization reusing the type argument vector of the

runtime/vm/intermediate_language_ia32.cc

Index: runtime/vm/intermediate_language_ia32.cc
===================================================================
--- runtime/vm/intermediate_language_ia32.cc	(revision 22154)
+++ runtime/vm/intermediate_language_ia32.cc	(working copy)
@@ -1875,7 +1875,9 @@
 
   // 'instantiator_reg' is the instantiator AbstractTypeArguments object
   // (or null).
-  if (!type_arguments().IsUninstantiatedIdentity()) {
+  if (!type_arguments().IsUninstantiatedIdentity() &&
+      !type_arguments().CanShareInstantiatorTypeArguments(
+          instantiator_class())) {
     // If the instantiator is null and if the type argument vector
     // instantiated from null becomes a vector of dynamic, then use null as
     // the type arguments.
@@ -1925,7 +1927,9 @@
 
   // instantiator_reg is the instantiator type argument vector, i.e. an
   // AbstractTypeArguments object (or null).
-  if (!type_arguments().IsUninstantiatedIdentity()) {
+  if (!type_arguments().IsUninstantiatedIdentity() &&
+      !type_arguments().CanShareInstantiatorTypeArguments(
+          instantiator_class())) {
     // If the instantiator is null and if the type argument vector
     // instantiated from null becomes a vector of dynamic, then use null as
     // the type arguments.
@@ -1968,7 +1972,9 @@
 
   // instantiator_reg is the instantiator AbstractTypeArguments object
   // (or null).
-  if (type_arguments().IsUninstantiatedIdentity()) {
+  if (type_arguments().IsUninstantiatedIdentity() ||
+      type_arguments().CanShareInstantiatorTypeArguments(
+          instantiator_class())) {
     // The instantiator was used in VisitExtractConstructorTypeArguments as the
     // instantiated type arguments, no proper instantiator needed.
     __ movl(instantiator_reg,