net-test: remove testRemovedQtaguid and testRemovedTcpMemSysctls

There's no pressing need to enforce this any more,
as they were really last present in 4.9 and 4.14 kernels.

While V can still run on 4.19+ kernels, V VTS is really
only for new launch kernels, which are 6.1/6.6 and have
*never* included these.

Furthermore the presence of the tcp sysctls is simply harmless,
and xt_qtaguid hasn't been supported (due to switch to eBPF)
since Android *S* (which also mandated a 4.9+ kernel).

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I46d7816409d8e42b348f105905b7146afa6bde3a