[NFC][Codegen][X86] Tests w/ final optimized IR of SROA-with-variably-indexed-loads (D140493)

32-byte ones are for consistency only, we really only care about
up to 16-byte on 64-bit and maybe up to 8-byte on 32-bit.

In 16byte ones, we are still having some redundant vec<->scalar traffic.

https://reviews.llvm.org/D140493