test: move test-net-connect-econnrefused from pummel to sequential

test-net-connect-econnrefused esems to run quickly on all platforms and
does not appear to need to be in the pummel directory. Move to
sequential.

PR-URL: #38462
Reviewed-By: Anto Aravinth <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: Trott