Test no_drop_no_swap for the pt-online-schema-change is broken

t/pt-online-schema-change/no_drop_no_swap.t is broken in current 3.x branch.

$ git branch

• 3.x

$ perl t/pt-online-schema-change/no_drop_no_swap.t
ok 1 - no swap-tables, drop-triggers, drop-new-table: triggers
ok 2 - no swap-tables, drop-triggers, drop-new-table: tables

1. Tests were run but no plan was declared and done_testing() was not seen.
2. Looks like your test exited with 2 just after 2.

$ git branch

• (detached from 2.2.19)
  3.x

$ perl t/pt-online-schema-change/no_drop_no_swap.t
ok 1 - no swap-tables, drop-triggers, drop-new-table: triggers
ok 2 - no swap-tables, drop-triggers, drop-new-table: tables
ok 3 - Sandbox servers
1..3

$ git bisect start 3.x 2.2.19
Bisecting: 665 revisions left to test after this (roughly 9 steps)
[a08b6779486db60a57983d62b5377eef1b606ccd] Fixed incorrect release date

$ git bisect run perl t/pt-online-schema-change/no_drop_no_swap.t

<snip>

a6e0b0d324c8404fb84d0ebac830749b4876d6e9 is the first bad commit
commit a6e0b0d324c8404fb84d0ebac830749b4876d6e9
Author: Carlos Salguero <[email protected]>
Date: Tue Oct 8 13:10:26 2019 -0300

WIP

:040000 040000 2203154c4d1ba291a253c37e7ec26b8d0cf54036 d5b5cf6f39171da7129388cf3317084ac344a51e M bin
:040000 040000 0da38789790028d126dec06e25389079861cab94 c9b57eb123748461fcd77edc87087beee9fde45c M lib
:040000 040000 3f1a57e4a4d554843614ce02904faaa8fe9ec3b2 1705cd739764bb2bdfc332cee9159eed709c3d03 M t
bisect run success