[GlobalISel] translate freeze to new generic G_FREEZE
Summary:
As a follow up to https://reviews.llvm.org/D29014, add translation
support for freeze.
Introduce a new generic instruction G_FREEZE and translate freeze to it.
Reviewers: dsanders, aqjune, arsenm, aditya_nandakumar, t.p.northover, lebedev.ri, paquette, aemerson
Reviewed By: aqjune, arsenm
Subscribers: fhahn, lebedev.ri, wdng, rovka, hiraditya, jfb, volkan, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77795