Remove testMinRequiredKernelVersion from kernel_feature_test.py

There is a better and equivalent version of this test in C++ in //system/netd/tests/kernel_test.cpp which is part of netd_integration_test which is part of VTS as well.

ie. this gets rid of the python dup.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I286bcb48ca60af22526cef3edb438b6b1a053206