VM: Avoid allocating strings when disassembling code.

runtime/vm/compiler.cc

 // Copyright (c) 2012, 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/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 1323 matching lines @@
                 Code::Handle(function.CurrentCode()).PayloadStart(),
                 Code::Handle(function.CurrentCode()).Size(),
                 per_compile_timer.TotalElapsedTime());
     }
 
     if (FLAG_support_debugger) {
       isolate->debugger()->NotifyCompilation(function);
     }
 
     if (FLAG_disassemble && FlowGraphPrinter::ShouldPrint(function)) {
-      SafepointOperationScope safepoint_scope(thread);
-      NoHeapGrowthControlScope no_growth_control;
       Disassembler::DisassembleCode(function, optimized);
     } else if (FLAG_disassemble_optimized &&
                optimized &&
                FlowGraphPrinter::ShouldPrint(function)) {
-      SafepointOperationScope safepoint_scope(thread);
-      NoHeapGrowthControlScope no_growth_control;
       Disassembler::DisassembleCode(function, true);
     }
 
     DEBUG_ONLY(CheckInliningIntervals(function));
     return Error::null();
   } else {
     Thread* const thread = Thread::Current();
     StackZone stack_zone(thread);
     Error& error = Error::Handle();
     // We got an error during compilation or it is a bailout from background
@@ skipping 949 matching lines @@
 
 
 bool BackgroundCompiler::IsDisabled() {
   UNREACHABLE();
   return true;
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart