Remove strong mode support from rest argument creation.

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index 113501dc3aabd9986a92dea413b0d1851bcd741d..32d6b3056c42be573e8220863fdc829697321985 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -276,9 +276,6 @@ void FullCodeGenerator::Generate() {
            StandardFrameConstants::kCallerSPOffset + offset);
     __ Mov(RestParamAccessDescriptor::rest_parameter_index(),
            Smi::FromInt(rest_index));
-    __ Mov(RestParamAccessDescriptor::language_mode(),
-           Smi::FromInt(language_mode()));
-    DCHECK(x1.is(RestParamAccessDescriptor::language_mode()));
 
     function_in_register_x1 = false;