VPP-1508 Fix for bug introduced in tests on use of repr.

VPP-1508 Fix for bug introduced in tests on use of repr.

This fixes the change from https://gerrit.fd.io/r/#/c/16175/

...

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Totals
======
Ran: 856 tests in 2123.0000 sec.
 - Passed: 667
 - Skipped: 157
 - Expected Fail: 0
 - Unexpected Success: 0
 - Failed: 32
Sum of execute time for each test: 1641.0832 sec.

==============
Worker Balance
==============
 - Worker 0 (416 tests) => 0:35:06.788054
 - Worker 1 (440 tests) => 0:31:13.814911
Test id                                                                                 Runtime (s)
--------------------------------------------------------------------------------------  -----------
test.test_vcl.VCLCutThruTestCase.test_ldp_cut_thru_bi_dir_nsock                         120.382
test.test_vcl.VCLThruHostStackGroupBTestCase.test_ldp_thru_host_stack_bi_dir_nsock       60.368
test.test_vcl.VCLIpv6ThruHostStackGroupBTestCase.test_ldp_thru_host_stack_bi_dir_nsock   60.356
test.test_igmp.TestIgmp.test_igmp_host                                                   47.411
test.test_reassembly.TestFIFReassembly.test_fif6                                         38.561
test.test_reassembly.TestFIFReassembly.test_fif4                                         37.045
test.test_gbp.TestGBP.test_gbp                                                           30.041
test.test_dhcp.TestDHCP.test_dhcp_proxy                                                  29.339
test.test_vcl.VCLCutThruTestCase.test_ldp_cut_thru_iperf3                                20.489
test.test_neighbor.ARPTestCase.test_arp                                                  19.004

Change-Id: Ic1565f14962f157d5041230de3aeeab0b85f21e1
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>