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

runtime/vm/flow_graph_compiler_mips.cc

Index: runtime/vm/flow_graph_compiler_mips.cc
===================================================================
--- runtime/vm/flow_graph_compiler_mips.cc	(revision 36662)
+++ runtime/vm/flow_graph_compiler_mips.cc	(working copy)
@@ -25,7 +25,6 @@
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(int, reoptimization_counter_threshold);
 DECLARE_FLAG(bool, enable_type_checks);
-DECLARE_FLAG(bool, eliminate_type_checks);
 
 
 FlowGraphCompiler::~FlowGraphCompiler() {
@@ -662,12 +661,6 @@
   __ BranchEqual(A0, reinterpret_cast<int32_t>(Object::null()), &is_assignable);
   __ delay_slot()->sw(A1, Address(SP, 0 * kWordSize));
 
-  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.
-    __ BranchEqual(A0, Object::transition_sentinel(), &is_assignable);
-  }
-
   // Generate throw new TypeError() if the type is malformed or malbounded.
   if (dst_type.IsMalformedOrMalbounded()) {
     __ addiu(SP, SP, Immediate(-4 * kWordSize));