Fix disassembly comments

runtime/vm/disassembler.cc

 // Copyright (c) 2011, 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/disassembler.h"
 
 #include "vm/assembler.h"
 #include "vm/globals.h"
 #include "vm/os.h"
 #include "vm/log.h"
@@ skipping 15 matching lines @@
       ISL_Print(" ");
     }
   }
   ISL_Print("%s", human_buffer);
   ISL_Print("\n");
 }
 
 
 void DisassembleToStdout::Print(const char* format, ...) {
   va_list args;
+
   va_start(args, format);
-  OS::VFPrint(stdout, format, args);
+  intptr_t len = OS::VSNPrint(NULL, 0, format, args);
   va_end(args);
+
+  char* p = reinterpret_cast<char*>(malloc(len+1));
+  va_start(args, format);
+  OS::VSNPrint(p, len, format, args);
+  va_end(args);
+
+  ISL_Print("%s", p);
+  free(p);
 }
 
 
 void DisassembleToJSONStream::ConsumeInstruction(char* hex_buffer,
                                                  intptr_t hex_size,
                                                  char* human_buffer,
                                                  intptr_t human_size,
                                                  uword pc) {
   uint8_t* pc_ptr = reinterpret_cast<uint8_t*>(pc);
   // Instructions are represented as three consecutive values in a JSON array.
@@ skipping 103 matching lines @@
     formatter->ConsumeInstruction(hex_buffer,
                                   sizeof(hex_buffer),
                                   human_buffer,
                                   sizeof(human_buffer),
                                   pc);
     pc += instruction_length;
   }
 }
 
 }  // namespace dart