[Temp][oz-wl] Fix crash when switching to console (VT) mode.
[Temp][oz-wl] Fix crash when switching to console (VT) mode.

Buffer swapping should not be synchronized so that the GPU process
is not blocked by waiting for a frame update from Weston.

BUG=TC-341

[This is oz-wl's 0007-Fix-crash-when-switching-to-console-VT-mode.patch]

It is not clear from ozone-wayland's pull request #300 if this change
has been submitted upstream.

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