Only pass isolate parameter to C helper functions that need it.

src/v8.h

Index: src/v8.h
diff --git a/src/v8.h b/src/v8.h
index e7ca0d2e32c6bf9e63eaa420a3b57103f18ee755..aa037d5b9bd9ef8bb2c453ffbbf960af5cdd06ad 100644
--- a/src/v8.h
+++ b/src/v8.h
@@ -101,7 +101,8 @@ class V8 : public AllStatic {
   // use a separate random state for internal random number
   // generation.
   static uint32_t RandomPrivate(Isolate* isolate);
-  static Object* FillHeapNumberWithRandom(Object* heap_number);
+  static Object* FillHeapNumberWithRandom(Object* heap_number,
+                                          Isolate* isolate);
 
   // Idle notification directly from the API.
   static bool IdleNotification();