tc-testing: don't access non-existent variable on exception

Since commit 255c1c7279ab ("tc-testing: Allow test cases to be skipped")
the variable test_ordinal doesn't exist in call_pre_case().
So it should not be accessed when an exception occurs.

This resolves the following splat:

...
During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File ".../tdc.py", line 1028, in <module>
main()
File ".../tdc.py", line 1022, in main
set_operation_mode(pm, parser, args, remaining)
File ".../tdc.py", line 966, in set_operation_mode
catresults = test_runner_serial(pm, args, alltests)
File ".../tdc.py", line 642, in test_runner_serial
(index, tsr) = test_runner(pm, args, alltests)
File ".../tdc.py", line 536, in test_runner
res = run_one_test(pm, args, index, tidx)
File ".../tdc.py", line 419, in run_one_test
pm.call_pre_case(tidx)
File ".../tdc.py", line 146, in call_pre_case
print('test_ordinal is {}'.format(test_ordinal))
NameError: name 'test_ordinal' is not defined

Fixes: 255c1c7279ab ("tc-testing: Allow test cases to be skipped")
Signed-off-by: Simon Horman <[e-mail]>
Acked-by: Jamal Hadi Salim <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/tc-testing/tdc.py

···
             except Exception as ee:
                 print('exception {} in call to pre_case for {} plugin'.
                       format(ee, pgn_inst.__class__))
-                print('test_ordinal is {}'.format(test_ordinal))
                 print('testid is {}'.format(caseinfo['id']))
                 raise