Remove strong mode support from rest argument creation.

src/arm/interface-descriptors-arm.cc

Index: src/arm/interface-descriptors-arm.cc
diff --git a/src/arm/interface-descriptors-arm.cc b/src/arm/interface-descriptors-arm.cc
index d2852f4f78bd7cee911a7d80e360a806ae62e252..b7fad7bee6154f97d599496a111efc8041465739 100644
--- a/src/arm/interface-descriptors-arm.cc
+++ b/src/arm/interface-descriptors-arm.cc
@@ -68,7 +68,6 @@ const Register ArgumentsAccessNewDescriptor::parameter_pointer() { return r3; }
 const Register RestParamAccessDescriptor::parameter_count() { return r2; }
 const Register RestParamAccessDescriptor::parameter_pointer() { return r3; }
 const Register RestParamAccessDescriptor::rest_parameter_index() { return r4; }
-const Register RestParamAccessDescriptor::language_mode() { return r1; }
 
 
 const Register ApiGetterDescriptor::function_address() { return r2; }