Add generalized CAS primitives of char/short/int size

Add generalized CAS primitives of char/short/int size

* src/atomic_ops/generalize-small.template
(AO_XSIZE_fetch_compare_and_swap_acquire,
AO_XSIZE_fetch_compare_and_swap_release,
AO_XSIZE_fetch_compare_and_swap_write,
AO_XSIZE_fetch_compare_and_swap_read, AO_XSIZE_fetch_compare_and_swap,
AO_XSIZE_fetch_compare_and_swap_full,
AO_XSIZE_fetch_compare_and_swap_release_write,
AO_XSIZE_fetch_compare_and_swap_acquire_read,
AO_XSIZE_fetch_compare_and_swap_dd_acquire_read,
AO_XSIZE_compare_and_swap_acquire, AO_XSIZE_compare_and_swap_release,
AO_XSIZE_compare_and_swap_write, AO_XSIZE_compare_and_swap_read,
AO_XSIZE_compare_and_swap, AO_XSIZE_compare_and_swap_full,
AO_XSIZE_compare_and_swap_release_write,
AO_XSIZE_compare_and_swap_acquire_read,
AO_XSIZE_compare_and_swap_dd_acquire_read): New template primitive
(code copied from generalize.h for AO_t); define the corresponding
AO_HAVE_XSIZE_x.
* src/atomic_ops/generalize-small.h: Regenerate.
* src/atomic_ops/generalize.h (AO_compare_and_swap_acquire,
AO_compare_and_swap_release, AO_compare_and_swap_write,
AO_compare_and_swap_read, AO_compare_and_swap,
AO_compare_and_swap_full, AO_compare_and_swap_release_write,
AO_compare_and_swap_acquire_read, AO_compare_and_swap_dd_acquire_read,
AO_fetch_compare_and_swap_acquire, AO_fetch_compare_and_swap_release,
AO_fetch_compare_and_swap_write, AO_fetch_compare_and_swap_read,
AO_fetch_compare_and_swap, AO_fetch_compare_and_swap_full,
AO_fetch_compare_and_swap_release_write,
AO_fetch_compare_and_swap_acquire_read,
AO_fetch_compare_and_swap_dd_acquire_read): Remove (since present in
the auto-generated generalize-small.h) together with the corresponding
AO_HAVE_x.