Fix threading problems in test-api when running on simulator

src/isolate.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 256 matching lines @@
   MaybeObject* scheduled_exception_;
   bool external_caught_exception_;
   SaveContext* save_context_;
   v8::TryCatch* catcher_;
 
   // Stack.
   Address c_entry_fp_;  // the frame pointer of the top c entry frame
   Address handler_;   // try-blocks are chained through the stack
 
 #ifdef USE_SIMULATOR
-#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
   Simulator* simulator_;
 #endif
-#endif  // USE_SIMULATOR
 
   Address js_entry_sp_;  // the stack pointer of the bottom JS entry frame
   // the external callback we're currently in
   ExternalCallbackScope* external_callback_scope_;
   StateTag current_vm_state_;
 
   // Generated code scratch locations.
   int32_t formal_count_;
 
   // Call back function to report unsafe JS accesses.
@@ skipping 1233 matching lines @@
 
 // Mark the native context with out of memory.
 inline void Context::mark_out_of_memory() {
   native_context()->set_out_of_memory(GetIsolate()->heap()->true_value());
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_