Remove many features when building product mode

runtime/vm/pages.cc

Index: runtime/vm/pages.cc
diff --git a/runtime/vm/pages.cc b/runtime/vm/pages.cc
index 937d7bc1094800f5b76e04a2f6f299bffa0c3ef7..caea245f67de75df0201fe0dd9155d3adcabc02e 100644
--- a/runtime/vm/pages.cc
+++ b/runtime/vm/pages.cc
@@ -673,6 +673,9 @@ void PageSpace::WriteProtect(bool read_only, bool include_code_pages) {
 
 
 void PageSpace::PrintToJSONObject(JSONObject* object) const {
+  if (!FLAG_support_service) {
+    return;
+  }
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   JSONObject space(object, "old");
@@ -713,6 +716,9 @@ class HeapMapAsJSONVisitor : public ObjectVisitor {
 
 void PageSpace::PrintHeapMapToJSONStream(
     Isolate* isolate, JSONStream* stream) const {
+  if (!FLAG_support_service) {
+    return;
+  }
   JSONObject heap_map(stream);
   heap_map.AddProperty("type", "HeapMap");
   heap_map.AddProperty("freeClassId",