Update V8 to r6101 as required by WebKit r74534

Change-Id: I7f84af8dd732f11898fd644b2c2b1538914cb78d
diff --git a/src/arm/simulator-arm.h b/src/arm/simulator-arm.h
index c37b3f7..7bfe76a 100644
--- a/src/arm/simulator-arm.h
+++ b/src/arm/simulator-arm.h
@@ -186,6 +186,10 @@
   // ICache checking.
   static void FlushICache(void* start, size_t size);
 
+  // Returns true if pc register contains one of the 'special_values' defined
+  // below (bad_lr, end_sim_pc).
+  bool has_bad_pc() const;
+
  private:
   enum special_values {
     // Known bad pc value to ensure that the simulator does not execute