Fix hot reload test mode in simdbc by supporting forced slow paths on simdbc

runtime/vm/simulator_dbc.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 <setjmp.h>  // NOLINT
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_DBC)
 
@@ skipping 1429 matching lines @@
       if (reinterpret_cast<uword>(SP) >= thread->stack_limit()) {
         Exit(thread, FP, SP + 1, pc);
         NativeArguments args(thread, 0, NULL, NULL);
         INVOKE_RUNTIME(DRT_StackOverflow, args);
       }
     }
     DISPATCH();
   }
 
   {
+    BYTECODE(CheckStackAlwaysExit, A);
+    {
+      Exit(thread, FP, SP + 1, pc);
+      NativeArguments args(thread, 0, NULL, NULL);
+      INVOKE_RUNTIME(DRT_StackOverflow, args);
+    }
+    DISPATCH();
+  }
+
+  {
     BYTECODE(DebugStep, A);
     if (thread->isolate()->single_step()) {
       Exit(thread, FP, SP + 1, pc);
       NativeArguments args(thread, 0, NULL, NULL);
       INVOKE_RUNTIME(DRT_SingleStepHandler, args);
     }
     DISPATCH();
   }
 
   {
@@ skipping 2280 matching lines @@
     pc_ = pc;
   }
 
   buf->Longjmp();
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC