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

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 90a3aa1152b4287accf2e8294efa8a6433ff20d9..9399ffc7a22fad9e01a0606a6db363cdbd53c09d 100644
--- a/src/isolate.cc
+++ b/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_)) {