Add --hot-reload-test-mode flag to embedder and wire it up to test.py

runtime/vm/isolate_reload.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/isolate_reload.h"
 
 #include "vm/become.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/hash_table.h"
 #include "vm/isolate.h"
 #include "vm/log.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/safepoint.h"
 #include "vm/service_event.h"
 #include "vm/stack_frame.h"
 #include "vm/thread.h"
 #include "vm/timeline.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, trace_reload, false, "Trace isolate reloading");
 DEFINE_FLAG(bool, identity_reload, false, "Enable checks for identity reload.");
 DEFINE_FLAG(int, reload_every, 0, "Reload every N stack overflow checks.");
 DEFINE_FLAG(bool, reload_every_optimized, true, "Only from optimized code.");
-
+DEFINE_FLAG(bool, reload_every_back_off, false,
+            "Double the --reload-every value after each reload.");
+DEFINE_FLAG(bool, check_reloaded, false,
+            "Assert that an isolate has reloaded at least once.")
 #ifndef PRODUCT
 
 #define I (isolate())
 #define Z (thread->zone())
 
 #define TIMELINE_SCOPE(name)                                                   \
     TimelineDurationScope tds##name(Thread::Current(),                         \
                                    Timeline::GetIsolateStream(),               \
                                    #name)
 
@@ skipping 1114 matching lines @@
         ASSERT(!super_cls.IsNull());
         super_cls.AddDirectSubclass(cls);
       }
     }
   }
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart