Remove SUBDIR ordering/uniquifying in *bin/Makefile

After the addition of SUBDIR.yes, uniquifying/ordering the SUBDIRs doesn't
make a whole lot of sense, and it's in effect a half measure.

Ordering SUBDIR (after adding SUBDIR.yes to it) in bsd.subdir.mk is a
separate change that warrants more discussion/testing, because while
the SUBDIR_PARALLEL work largely fixed dependency ordering for SUBDIRs,
there might be downstream FreeBSD consumers that rely on the SUBDIR
ordering.

MFC after: 2 months
Reviewed by: bdrewery
Differential Revision: D11398