[DAG] Ensure more Legal BUILD_VECTOR elements types in shuffle->And combine

This is a followup to D131350, which caused another problem for i64
types being split into i32 on i32 targets. This patch tries to make sure
that either Illegal types are OK, or that the element types of a
buildvector are legal and bigger than or equal to the size of the
original elements.

Differential Revision: https://reviews.llvm.org/D131883

(cherry picked from commit dfc95bab)