Remove deprecated v8::base::OS::nan_value().

src/base/platform/platform.h

Index: src/base/platform/platform.h
diff --git a/src/base/platform/platform.h b/src/base/platform/platform.h
index 0bf102723acfd74d6d130e2a6f01ae5e1975d6e8..07155f7a58780e0f592dac63e82ece2925ad8cdf 100644
--- a/src/base/platform/platform.h
+++ b/src/base/platform/platform.h
@@ -246,9 +246,6 @@ class OS {
   // using --never-compact) if accurate profiling is desired.
   static void SignalCodeMovingGC();
 
-  // Returns the double constant NAN
-  static double nan_value();
-
   // Support runtime detection of whether the hard float option of the
   // EABI is used.
   static bool ArmUsingHardFloat();