In order to discard nodes not capable of running centos 9 launch node
discards x86_64 nodes that don't support sse4_2. However, this check
doesn't make sense for aarch64 nodes (like our arm nodepool builder).
Only check sse4_2 support when the machine type is x86_64.
Change-Id: If06c834be5e7189ddd8ee5b746f50e7bdb9f95d3
54da0c008f