finally remove the immAllOnesV_bc/immAllZerosV_bc patterns

and those derived from them.  These are obnoxious because
they were written as: PatLeaf<(bitconvert).  Not having an
argument was foiling adding better type checking for operand
count matching up with what was required (in this case,
bitconvert always requires an operand!)

llvm-svn: 99759