ci/tracie: Fix apitrace dump using "less" which isn't in the ARM rootfs.

You would get no output during the "find the last frame" step of the trace
replay.

Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5433>

.gitlab-ci/tracie-runner-gl.sh

@@ -25,6 +25,9 @@ export EGL_PLATFORM="surfaceless"
 export DISPLAY=
 export WAFFLE_PLATFORM="surfaceless_egl"
 
+# Our rootfs may not have "less", which apitrace uses during apitrace dump
+export PAGER=cat
+
 RESULTS=`pwd`/results
 mkdir -p $RESULTS