Fix all-reduce int tests by host-registering memrefs.
Reduce amount of boiler plate to register host memory.
Summary: Fix all-reduce int tests by host-registering memrefs.
Reviewed By: herhut
Subscribers: clementval, mehdi_amini, rriddle, jpienaar, burmako, shauheen, antiagainst, nicolasvasilache, arpith-jacob, mgester, lucyrfox, liufengdb, Joonsoo, llvm-commits
Differential Revision: https://reviews.llvm.org/D76563