Revert "Do not save last command/pipe/regex in register when history is disabled"
Revert "Do not save last command/pipe/regex in register when history is disabled"

This reverts commit 55621fb4cc9c01972317182dd6a8ed3ced0e1f9e.

This should not be necessary as :exec/eval already save those registers
and reset them by default, and it breaks the ability to use those
registers during an eval/exec (as the commands behave differently)

occivink/kakoune,Somasis/kakoune,alexherbo2/kakoune,jjthrash/kakoune,casimir/kakoune,alexherbo2/kakoune,Somasis/kakoune,occivink/kakoune,casimir/kakoune,mawww/kakoune,danr/kakoune,alexherbo2/kakoune,mawww/kakoune,mawww/kakoune,danr/kakoune,Somasis/kakoune,occivink/kakoune,casimir/kakoune,jjthrash/kakoune,danr/kakoune,casimir/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,jkonecny12/kakoune,danr/kakoune,occivink/kakoune,lenormf/kakoune,Somasis/kakoune,jkonecny12/kakoune,lenormf/kakoune,mawww/kakoune,jjthrash/kakoune,jjthrash/kakoune,lenormf/kakoune,lenormf/kakoune,jkonecny12/kakoune