winex11: Fix ctrl-<symbol> to generate codes below 0x20 where necessary.

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=13631

Your paranoid android.


=== wvistau64 (32 bit input) ===
input.c:731: Test failed:  0 (a4/0): 10 from 01 -> 00 unexpected
input.c:731: Test failed:  0 (a4/0): 11 from 01 -> 00 unexpected
input.c:731: Test failed:  0 (a4/0): a0 from 01 -> 00 unexpected
input.c:731: Test failed:  0 (a4/0): a2 from 01 -> 00 unexpected