[X86] Rewrite the add/mul/or/and reduction intrinsics to make better use of...

[X86] Rewrite the add/mul/or/and reduction intrinsics to make better use of other intrinsics and remove undef shuffle indices.

Similar to what was done to max/min recently.

These already reduced the vector width to 256 and 128 bit as we go unlike the original max/min code.

Differential Revision: https://reviews.llvm.org/D48346

llvm-svn: 335253