Replace lrint(3), lrintf(3), llrint(3) and llrintf(3) implementations with

Replace lrint(3), lrintf(3), llrint(3) and llrintf(3) implementations with
the same implementation that we're already using for lrintl(3) and llrintl(3).
The old implementations were derived from code from NetBSD that didn't pass
the lib/libm/msun/lrint_test regress test.  NetBSD replaced their
implementation with the FreeBSD implementation of this code which we were
already using for lrintl(3) and llrintl(3).  This fixes the regress test.

ok bluhm@, millert@