[Instcombine]Transform reduction+(sext/zext(<n x i1>) to <n x im>) to...

[Instcombine]Transform reduction+(sext/zext(<n x i1>) to <n x im>) to [-]zext/trunc(ctpop(bitcast <n x i1> to in)) to im.

Some of the SPEC tests end up with reduction+(sext/zext(<n x i1>) to <n x im>) pattern, which can be transformed to [-]zext/trunc(ctpop(bitcast <n x i1> to in)) to im.
Also, reduction+(<n x i1>) can be transformed to ctpop(bitcast <n x i1> to in) & 1 != 0.

Differential Revision: https://reviews.llvm.org/D105587