Followup to 2c7b47ee5d and 50481d06d2.
[Test pattern page](https://test.winehq.org/data/patterns.html#ntdll:exception)
[Testbot run with this patch.](https://testbot.winehq.org/JobDetails.pl?Key=157964)
This makes 32-bit systems also take the upper branch of the if.
CC: @gofman, I hope this matches the purpose of the test?
-- v2: ntdll/tests: Make single step test succeed for 32-bit systems.