[X86][SSE] combineHorizontalPredicateResult - improve all_of(X == 0) for vXi64 on pre-SSE41 targets

Without SSE41 we don't have the PCMPEQQ instruction, making cmp-with-zero reductions more complicated than necessary. We can compare as vXi32 (PCMPEQD) and tweak the MOVMSK comparison to test upper/lower DWORD comparisons.

This pre-fixes something that occurs with null tests for vectors of (64-bit) pointers such as in PR35129.