Remove default value for number of threads in Isolate::Init.

Just fixing a TODO.

R=jochen@chromium.org

Review URL: https://codereview.chromium.org/978773002

Cr-Commit-Position: refs/heads/master@{#26987}

src/isolate.cc

@@ -2054,15 +2054,6 @@ bool Isolate::Init(Deserializer* des) {
     set_event_logger(Logger::DefaultEventLoggerSentinel);
   }
 
-  // Set default value if not yet set.
-  // TODO(yangguo): move this to ResourceConstraints::ConfigureDefaults
-  // once ResourceConstraints becomes an argument to the Isolate constructor.
-  if (max_available_threads_ < 1) {
-    // Choose the default between 1 and 4.
-    max_available_threads_ =
-        Max(Min(base::SysInfo::NumberOfProcessors(), 4), 1);
-  }
-
   if (FLAG_trace_hydrogen || FLAG_trace_hydrogen_stubs) {
     PrintF("Concurrent recompilation has been disabled for tracing.\n");
   } else if (OptimizingCompilerThread::Enabled(max_available_threads_)) {