Update v8 to bleeding_edge revision 3784
diff --git a/src/assembler.cc b/src/assembler.cc
index fcdb14a..dbf2742 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -655,7 +655,7 @@
 #elif V8_TARGET_ARCH_ARM
   function = FUNCTION_ADDR(RegExpMacroAssemblerARM::CheckStackGuardState);
 #else
-  UNREACHABLE("Unexpected architecture");
+  UNREACHABLE();
 #endif
   return ExternalReference(Redirect(function));
 }