Fix issues when changing FLAG_concurrent_recompilation after init.

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 8676 matching lines @@
   if (FLAG_deopt_every_n_times) {
     return Smi::FromInt(6);  // 6 == "maybe deopted".
   }
   return function->IsOptimized() ? Smi::FromInt(1)   // 1 == "yes".
                                  : Smi::FromInt(2);  // 2 == "no".
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_UnblockConcurrentRecompilation) {
   RUNTIME_ASSERT(FLAG_block_concurrent_recompilation);
+  RUNTIME_ASSERT(isolate->concurrent_recompilation_enabled());
   isolate->optimizing_compiler_thread()->Unblock();
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetOptimizationCount) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 0);
   return Smi::FromInt(function->shared()->opt_count());
@@ skipping 6391 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal