selftests: tc-testing: remove buildebpf plugin

selftests: tc-testing: remove buildebpf plugin

As tdc only tests loading/deleting and anything more complicated is
better left to the ebpf test suite, provide a pre-compiled version of
'action.c' and don't bother compiling it in kselftests or on the fly
at all.

Cc: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20231124154248.315470-2-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>