- fix some cases where we are using uninitialized memory

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index 61a04e2206af9b7ad309f0f0d4ac069c57c2dfd0..a90193af05e31f99a3d70aa5d20becd7420382de 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -839,6 +839,11 @@ class Isolate : public BaseIsolate {
   Monitor* spawn_count_monitor_;
   intptr_t spawn_count_;
 
+#define ISOLATE_METRIC_VARIABLE(type, variable, name, unit)                    \
+  type metric_##variable##_;
+  ISOLATE_METRIC_LIST(ISOLATE_METRIC_VARIABLE);
+#undef ISOLATE_METRIC_VARIABLE
+
   // Has a reload ever been attempted?
   bool has_attempted_reload_;
   intptr_t no_reload_scope_depth_;  // we can only reload when this is 0.
@@ -847,11 +852,6 @@ class Isolate : public BaseIsolate {
   IsolateReloadContext* reload_context_;
   int64_t last_reload_timestamp_;
 
-#define ISOLATE_METRIC_VARIABLE(type, variable, name, unit)                    \
-  type metric_##variable##_;
-  ISOLATE_METRIC_LIST(ISOLATE_METRIC_VARIABLE);
-#undef ISOLATE_METRIC_VARIABLE
-
 
   static Dart_IsolateCreateCallback create_callback_;
   static Dart_IsolateShutdownCallback shutdown_callback_;