Get rid of unused field has_compiled_code_ from the Isolate structure.

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 1143 matching lines @@
             FinalizeCompilation(&assembler, &graph_compiler, flow_graph);
           }
           // TODO(srdjan): Enable this and remove the one from
           // 'BackgroundCompiler::CompileOptimized' once cause of time-outs
           // is resolved.
           // if (isolate()->heap()->NeedsGarbageCollection()) {
           //   isolate()->heap()->CollectAllGarbage();
           // }
         }
       }
-      // Mark that this isolate now has compiled code.
-      isolate()->set_has_compiled_code(true);
       // Exit the loop and the function with the correct result value.
       is_compiled = true;
       done = true;
     } else {
       // We bailed out or we encountered an error.
       const Error& error = Error::Handle(thread()->sticky_error());
 
       if (error.raw() == Object::branch_offset_error().raw()) {
         // Compilation failed due to an out of range branch offset in the
         // assembler. We try again (done = false) with far branches enabled.
@@ skipping 1140 matching lines @@
 
 
 bool BackgroundCompiler::IsDisabled() {
   UNREACHABLE();
   return true;
 }
 
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart