find good availability zone for the user-provided instance type (#1935)
find good availability zone for the user-provided instance type (#1935)

Co-authored-by: Ben Clifford <6e9c823d93e7dad5e7e2198704c60762764c20c1@hawaga.org.uk>
Parsl/parsl,Parsl/parsl,Parsl/parsl,Parsl/parsl