arrow

ARROW-18080: [C++] Remove gcc <= 4.9 workarounds (#14441)

This is most of them I could find. There's another one in `python/pyarrow/src/arrow/python/datetime.cc` to remove but it's more involved.

Authored-by: Neal Richardson <neal.p.richardson@gmail.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>