glmark2: drop terrain trace

Traced before commit `terrain: Fix precision handling in noise shader`
which fixes the trace and makes output consistent on different HW.

Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: David Heidelberg <david.heidelberg@collabora.com>
Part-of: <gfx-ci/tracie/traces-db!50>