Fixes <https://issues.guix.gnu.org/40144>.
Until now, the '--rounds' option, when also using '--check', was ignored.
This change makes it possible to use both, so that an item that has already
been built once can be rebuilt as many times as desired.
* nix/libstore/build.cc: Remove the conditionals causing the daemon to
complete a build task early when 'buildMode' is equal to 'nix::bmCheck'.
Reported-by: Brice Waegeneire <brice@waegenei.re>