MIDI tracks don't map one-to-one to segment tracks, so it doesn't make sense to use a
"get_next_track()" interface.

The field is set but no longer read from.

Apparently, 1454ffe7 introduced
the assumption that the font passed to gdip_format_string is
non-NULL, and GdipAddPathString wasn't passing it in.

When hwnd is specified, it is because it received a direct host input,
so switch the input desktop to match the one that is receiving it.

We don't validate that the sending thread uses the same desktop as the
target window: it may not even be the case for drivers with a separate
thread that listens on input events.

This reverts commit 6f9d2080.

6f9d2080 was committed to work around a Nvidia driver bug that can cause vkGetRandROutputDisplayEXT()
to generate an X exception and crash applications. The bug is later fixed in Nvidia driver 450.56.11
and newer. Thus 6f9d2080 is no longer necessary on the newer Nvidia drivers.

Then after 18ae96e5, another bug in the Nvidia driver can cause vkGetRandROutputDisplayEXT() to hang
forever when XLockDisplay() is called before vkGetRandROutputDisplayEXT() and this bug is still not
fixed and affects multiple applications. Reverting 6f9d2080 allows us to work around the
vkGetRandROutputDisplayEXT() hang bug because then it no longer calls XLockDisplay() before
vkGetRandROutputDisplayEXT().

Nvidia driver 455 was released on September 9th 2020 so hopefully the fix is already widespread. We
could theoretically still keep 6f9d2080 on older Nvidia drivers by doing version checks. But it's
more straightforward to remove the workaround since it's not a bug of Wine.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=53428

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=48110

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=46773

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=56360