tests: tag the tests that do not work with multi-worker configuration

If the multi-worker default VPP configuration is triggered by
setting VPP_WORKER_CONFIG="workers 2", some of the tests fail
for various reasons.

It's a substantial number, so this change marks all of the
testsets that have this issue, such that they can be addressed
later independently.

Type: test
Change-Id: I4f77196499edef3300afe7eabef9cbff91f794d3
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>
diff --git a/src/vnet/bfd/test/test_bfd.py b/src/vnet/bfd/test/test_bfd.py
index 71904a8..3e6453c 100644
--- a/src/vnet/bfd/test/test_bfd.py
+++ b/src/vnet/bfd/test/test_bfd.py
@@ -21,6 +21,7 @@
 
 from bfd import VppBFDAuthKey, BFD, BFDAuthType, VppBFDUDPSession, \
     BFDDiagCode, BFDState, BFD_vpp_echo
+from framework import tag_fixme_vpp_workers
 from framework import VppTestCase, VppTestRunner, running_extended_tests
 from framework import tag_run_solo
 from util import ppp
@@ -1488,6 +1489,7 @@
 
 
 @tag_run_solo
+@tag_fixme_vpp_workers
 class BFD6TestCase(VppTestCase):
     """Bidirectional Forwarding Detection (BFD) (IPv6) """