Don't require eliminating certain type checks in unoptimized compilation.

runtime/vm/flow_graph_compiler_ia32.cc

Index: runtime/vm/flow_graph_compiler_ia32.cc
===================================================================
--- runtime/vm/flow_graph_compiler_ia32.cc	(revision 36662)
+++ runtime/vm/flow_graph_compiler_ia32.cc	(working copy)
@@ -28,7 +28,6 @@
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(int, reoptimization_counter_threshold);
 DECLARE_FLAG(bool, enable_type_checks);
-DECLARE_FLAG(bool, eliminate_type_checks);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
 DECLARE_FLAG(bool, enable_simd_inline);
 
@@ -676,16 +675,6 @@
   __ cmpl(EAX, raw_null);
   __ j(EQUAL, &is_assignable);
 
-  if (!FLAG_eliminate_type_checks || dst_type.IsMalformed()) {
-    // If type checks are not eliminated during the graph building then
-    // a transition sentinel can be seen here.
-    const Immediate& raw_transition_sentinel =
-        Immediate(reinterpret_cast<intptr_t>(
-            Object::transition_sentinel().raw()));
-    __ cmpl(EAX, raw_transition_sentinel);
-    __ j(EQUAL, &is_assignable);
-  }
-
   // Generate throw new TypeError() if the type is malformed or malbounded.
   if (dst_type.IsMalformedOrMalbounded()) {
     __ PushObject(Object::ZoneHandle());  // Make room for the result.