selftests/net: Split netdevsim tests from HW tests in nk_qlease

selftests/net: Split netdevsim tests from HW tests in nk_qlease

As pointed out in 3d2c3d2eea9a ("selftests: net: py: explicitly forbid
multiple ksft_run() calls"), ksft_run() cannot be called multiple times.

Move the netdevsim-based queue lease tests to selftests/net/ so that
each file has exactly one ksft_run() call.

The HW tests (io_uring ZC RX, queue attrs, XDP with MP, destroy) remain
in selftests/drivers/net/hw/.

Fixes: 65d657d80684 ("selftests/net: Add queue leasing tests with netkit")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/netdev/20260409181950.7e099b6c@kernel.org
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20260413220809.604592-3-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>