remove netd_test NetdBpfTest.testBpfSkbChangeHeadAboveMTU()

This netd test depends on structure/map definitions from
a mainline module which is verbotten.

Test: atest, TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I96667bd0f73665553da49f3b6c1ac8a8a5a76e25