std-compat: Simplify SEASTAR_COPY_ELISION definition
std-compat: Simplify SEASTAR_COPY_ELISION definition

Signed-off-by: Rafael Ávila de Espíndola <1975039f9046bf513b77c0c5639a0efc25f00e7f@scylladb.com>

syuu1228/seastar,avikivity/seastar,dreamsxin/seastar,avikivity/seastar,scylladb/seastar,syuu1228/seastar,avikivity/seastar,dreamsxin/seastar,dreamsxin/seastar,scylladb/seastar,cloudius-systems/seastar,scylladb/seastar,cloudius-systems/seastar,cloudius-systems/seastar,syuu1228/seastar