Mesh conformance tests are hard to debug

[howardjohn]

=== RUN   TestGatewayConformance/MeshBasic/0_request_to_'echo'_should_receive_a_200
    http.go:166: Failed to parse host "echo": address echo: missing port in address
    pod.go:64: Request [client http://echo --method=GET] failed, not ready yet: command terminated with exit code 1 (after 10.61µs)
    http.go:166: Failed to parse host "echo": address echo: missing port in address
    pod.go:64: Request [client http://echo --method=GET] failed, not ready yet: command terminated with exit code 1 (after 1.251942543s)
    http.go:166: Failed to parse host "echo": address echo: missing port in address
    pod.go:64: Request [client http://echo --method=GET] failed, not ready yet: command terminated with exit code 1 (after 2.356704437s)

Example failure.

It would be nice to see the output of the command for debugging