[mlir][vector] Constant fold sub-vector extraction

This generalizes the existing fold for `ExtractOp(non-splat constant)`
to work with vector results. The vector case is handled by extracting
the subrange of attribute array.

My main use it to clean up code generated by the Wide Integer Emulation
pass.

Reviewed By: antiagainst

Differential Revision: https://reviews.llvm.org/D138690