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

runtime/vm/flow_graph_compiler_ia32.cc

Index: runtime/vm/flow_graph_compiler_ia32.cc
diff --git a/runtime/vm/flow_graph_compiler_ia32.cc b/runtime/vm/flow_graph_compiler_ia32.cc
index 2c7b3353684aa2703dcde1aa8f294c78153a4184..d0b020a7a532d820a3d821de43d55ff59c887ed7 100644
--- a/runtime/vm/flow_graph_compiler_ia32.cc
+++ b/runtime/vm/flow_graph_compiler_ia32.cc
@@ -1030,7 +1030,10 @@ void FlowGraphCompiler::EmitFrameEntry() {
 void FlowGraphCompiler::CompileGraph() {
   InitCompiler();
 
-  TryIntrinsify();
+  if (TryIntrinsify()) {
+    // Intrinsic has no fall through.
+    return;
+  }
 
   EmitFrameEntry();