perftune.py should switch to AWS IMDSv2 calls

[fee-mendes]

perftune's __check_host_type method uses IMDSv1 for retrieving instance metadata. It turns out that - as described in https://github.com/scylladb/scylla/issues/10490 - Ec2 instances may have only IMDSv2 HTTP calls allowed.

When requests to IMDSv1 fail, calling is_aws_i3_non_metal_instance() will evaluate to False, which means that i3.nonmetal instance types will get tuned as if they weren't i3 instances.