Remove strong mode support from rest argument creation.

src/mips/interface-descriptors-mips.cc

Index: src/mips/interface-descriptors-mips.cc
diff --git a/src/mips/interface-descriptors-mips.cc b/src/mips/interface-descriptors-mips.cc
index 589d77ae9e6841efbcb7a4f62b8b4edb5d8754cf..3f4fb3802828c796ff4a776536eae5a8f14785a9 100644
--- a/src/mips/interface-descriptors-mips.cc
+++ b/src/mips/interface-descriptors-mips.cc
@@ -66,7 +66,6 @@ const Register ArgumentsAccessNewDescriptor::parameter_pointer() { return a3; }
 const Register RestParamAccessDescriptor::parameter_count() { return a2; }
 const Register RestParamAccessDescriptor::parameter_pointer() { return a3; }
 const Register RestParamAccessDescriptor::rest_parameter_index() { return a1; }
-const Register RestParamAccessDescriptor::language_mode() { return a0; }
 
 
 const Register ApiGetterDescriptor::function_address() { return a2; }