Use a breakpoint instruction for a stop message on arm instead of

runtime/vm/assembler_arm.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_ASSEMBLER_ARM_H_
 #define VM_ASSEMBLER_ARM_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_arm.h directly; use assembler.h instead.
 #endif
@@ skipping 468 matching lines @@
 
   void ldrex(Register rd, Register rn, Condition cond = AL);
   void strex(Register rd, Register rt, Register rn, Condition cond = AL);
 
   // Miscellaneous instructions.
   void clrex();
   void nop(Condition cond = AL);
 
   // Note that gdb sets breakpoints using the undefined instruction 0xe7f001f0.
   void bkpt(uint16_t imm16);
-  void svc(uint32_t imm24, Condition cond = AL);
 
   // Floating point instructions (VFPv3-D16 and VFPv3-D32 profiles).
   void vmovsr(SRegister sn, Register rt, Condition cond = AL);
   void vmovrs(Register rt, SRegister sn, Condition cond = AL);
   void vmovsrr(SRegister sm, Register rt, Register rt2, Condition cond = AL);
   void vmovrrs(Register rt, Register rt2, SRegister sm, Condition cond = AL);
   void vmovdrr(DRegister dm, Register rt, Register rt2, Condition cond = AL);
   void vmovrrd(Register rt, Register rt2, DRegister dm, Condition cond = AL);
   void vmovdr(DRegister dd, int i, Register rt, Condition cond = AL);
   void vmovs(SRegister sd, SRegister sm, Condition cond = AL);
@@ skipping 623 matching lines @@
                      Register new_value,
                      FieldContent old_content);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM_H_