xclient.send_request() should just take a Request object and handle
to_bytes with the right byte order. This avoids typos/copy-paste errors
in tests when the byte order changes between tests.
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2216>
The test sends a PresentPixmap request with a notify entry from a
byte-swapped client. Without the fix, the window ID in the notify
is not swapped, causing dixLookupWindow to fail with BadWindow.
With the fix, the window ID is correctly interpreted.
See 925edb6c9e ("present: Fix missing byte swaps in sproc_present_pixmap()")
Assisted-by: Claude:claude-claude-opus-4-6
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2212>