Remove fields from Isolate in Product mode

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
diff --git a/runtime/vm/flow_graph_compiler.cc b/runtime/vm/flow_graph_compiler.cc
index 750541cb3e2f3fd780bcde9596e1b1cbfba52b70..6dadee8d3dba9245ef726b1499257b1f0eed07ca 100644
--- a/runtime/vm/flow_graph_compiler.cc
+++ b/runtime/vm/flow_graph_compiler.cc
@@ -294,6 +294,7 @@ bool FlowGraphCompiler::CanOSRFunction() const {
 }
 
 bool FlowGraphCompiler::ForceSlowPathForStackOverflow() const {
+#if !defined(PRODUCT)
   if ((FLAG_stacktrace_every > 0) || (FLAG_deoptimize_every > 0) ||
       (isolate()->reload_every_n_stack_overflow_checks() > 0)) {
     return true;
@@ -308,6 +309,7 @@ bool FlowGraphCompiler::ForceSlowPathForStackOverflow() const {
              FLAG_deoptimize_filter) != NULL) {
     return true;
   }
+#endif  // !defined(PRODUCT)
   return false;
 }