Partially revert r26703 and omit regular code generation for implicit accessors.

runtime/vm/flow_graph_compiler_mips.cc

Index: runtime/vm/flow_graph_compiler_mips.cc
diff --git a/runtime/vm/flow_graph_compiler_mips.cc b/runtime/vm/flow_graph_compiler_mips.cc
index 0cc605ce82f9bff01155b6aa9bef54a768c6ba37..eb3520d40901325755d688fdcfbf2b4829c87fef 100644
--- a/runtime/vm/flow_graph_compiler_mips.cc
+++ b/runtime/vm/flow_graph_compiler_mips.cc
@@ -1040,7 +1040,10 @@ void FlowGraphCompiler::EmitFrameEntry() {
 void FlowGraphCompiler::CompileGraph() {
   InitCompiler();
 
-  TryIntrinsify();
+  if (TryIntrinsify()) {
+    // Intrinsic has no fall through.

[srdjan, 2015/10/05 17:38:25]

This is not quite true. There are intrinsics that have no fall through and still
return false.  Synchronize it with the comment in TryIntrinsify.

+    return;
+  }
 
   EmitFrameEntry();