[instruction scheduler] fix ArchDebugBreak.

src/arm64/simulator-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 #include <cmath>
 #include <cstdarg>
 
 #if V8_TARGET_ARCH_ARM64
 
@@ skipping 3871 matching lines @@
       } else if (instr->ImmException() == kImmExceptionIsUnreachable) {
         fprintf(stream_, "Hit UNREACHABLE marker at PC=%p.\n",
                 reinterpret_cast<void*>(pc_));
         abort();
 
       } else {
         base::OS::DebugBreak();
       }
       break;
     }
-
+    case BRK:
+      base::OS::DebugBreak();
+      break;
     default:
       UNIMPLEMENTED();
   }
 }
 
 
 void Simulator::DoPrintf(Instruction* instr) {
   DCHECK((instr->Mask(ExceptionMask) == HLT) &&
               (instr->ImmException() == kImmExceptionIsPrintf));
 
@@ skipping 298 matching lines @@
   processor->prev_ = nullptr;
   processor->next_ = nullptr;
 }
 
 #endif  // USE_SIMULATOR
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64