i965: Flush batchbuffer containing the query on glQueryCounter.

i965: Flush batchbuffer containing the query on glQueryCounter.

This change fixes a regression with timer queries introduced with
commit 3eb6258. There the pending batchbuffer is flushed
only if glEndQuery is executed. This present change adds such
a flush to glQueryCounter which also schedules a value query
just like glEndQuery does. The patch fixes GPU timer queries
going mad from within osgviewer.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Mathias Froehlich <Mathias.Froehlich@web.de>
Cc: mesa-stable@lists.freedesktop.org
(cherry picked from commit 1e1d5456ba3dff82301ad4bbdde2fb6e2f562fe3)