Improve hot reload test mode

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index 7f1df6d9143786a7128e5c73f52e8e833745beb2..10e75a581f2063249cea2fb8cfb695aa1bb38aef 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -632,6 +632,12 @@ class Isolate : public BaseIsolate {
 
   void StopBackgroundCompiler();
 
+  intptr_t reload_every_n_stack_overflow_checks() const {
+    return reload_every_n_stack_overflow_checks_;
+  }
+
+  void MaybeIncreaseReloadEveryNStackOverflowChecks();
+
  private:
   friend class Dart;  // Init, InitOnce, Shutdown.
   friend class IsolateKillerVisitor;  // Kill().
@@ -815,6 +821,8 @@ class Isolate : public BaseIsolate {
   // Has a reload ever been attempted?
   bool has_attempted_reload_;
   intptr_t no_reload_scope_depth_;  // we can only reload when this is 0.
+  // Per-isolate copy of FLAG_reload_every.
+  intptr_t reload_every_n_stack_overflow_checks_;
   IsolateReloadContext* reload_context_;
 
 #define ISOLATE_METRIC_VARIABLE(type, variable, name, unit)                    \