Fix `codegen_atomic_binop` for `atomic_ptr` (#3047) #6182

Job	Run time
benchcomp-tests	4m 20s
bookrunner	14m 19s
perf	37m 59s
regression (macos-13)	36m 28s
regression (ubuntu-20.04)	20m 15s
write-json-symtab-regression	12m 17s
regression (ubuntu-22.04)	21m 58s
	2h 27m 36s

Provide feedback