[CIR] Implemented get/set for volatile bitfields (#151875)
This PR adds support for loading and storing volatile bit-field members
according to the AAPCS specification.
> A volatile bit-field must always be accessed using an access width
appropriate to the type of its container, except when any of the
following are true:
>
> * The bit-field container overlaps with a zero-length bit-field.
> * The bit-field container overlaps with a non-bit-field member.
For example, if a bit-field is declared as `int`, the load/store must
use a 32-bit access, even if the field itself is only 3 bits wide.
