Deleted some puzzling code in flops(), a routine which locates redundant

Deleted some puzzling code in flops(), a routine which locates redundant
std/ldd pairs and eliminates the ldd, turning the std into a write to a dead
register which is in turn removed by bflow().  The original coder apparently
wanted to re-run bflow() on all the instructions between the std and the ldd;
this is a gross error, since the uses[] information has been destroyed and
useful instructions can be inadvertently deleted.

SCCS-vsn: old/pcc/c2.tahoe/c21.c 1.8