src: replace FIXED_ONE_BYTE_STRING with Environment-cached strings

src: replace FIXED_ONE_BYTE_STRING with Environment-cached strings · nodejs/node@abecdcb

Original file line number	Diff line number	Diff line change
`@@ -738,11 +738,10 @@ static void Initialize(Local<Object> target,`
`738`	`738`
`739`	`739`	`Local<FunctionTemplate> length_getter =`
`740`	`740`	`FunctionTemplate::New(isolate, StorageLengthGetter);`
`741`		`- ctor_tmpl->PrototypeTemplate()->SetAccessorProperty(`
`742`		`-FIXED_ONE_BYTE_STRING(isolate, "length"),`
`743`		`- length_getter,`
`744`		`- Local<FunctionTemplate>(),`
`745`		`- DontDelete);`
	`741`	`+ ctor_tmpl->PrototypeTemplate()->SetAccessorProperty(env->length_string(),`
	`742`	`+ length_getter,`
	`743`	`+ Local<FunctionTemplate>(),`
	`744`	`+ DontDelete);`
`746`	`745`
`747`	`746`	`SetProtoMethod(isolate, ctor_tmpl, "clear", Clear);`
`748`	`747`	`SetProtoMethodNoSideEffect(isolate, ctor_tmpl, "getItem", GetItem);`