tests: Disable the bpftrace test

The package does not build at the moment:
https://github.com/linuxkit/linuxkit/issues/3296

Signed-off-by: Rolf Neugebauer <rn@rneugeba.io>

test/cases/040_packages/002_bpftrace/test.sh

@@ -1,5 +1,6 @@
 #!/bin/sh
 # SUMMARY: Check that the bpftrace package works
+# LABELS: disabled
 # REPEAT:
 
 set -e