[libc++][NFC] Reduce use of __add_lvalue_reference_t
#6586
| Job | Run time |
|---|---|
| 1m 39s | |
| 1m 39s |
__add_lvalue_reference_t
#6586
| Job | Run time |
|---|---|
| 1m 39s | |
| 1m 39s |