[GlobalISel] Translate shufflevector

Reviewers: qcolombet, aditya_nandakumar, t.p.northover, javed.absar, ab, dsanders

Reviewed By: javed.absar

Subscribers: dberris, rovka, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D30962

llvm-svn: 298347