ci: Enable building the testing drivers with perfetto.

We've talked about being able to capture perfetto traces from CI jobs for
a while, and this would be a step toward that.  Mostly it's that we
occasionally break the perfetto build, so let's make sure we don't do
that.

Acked-by: Rob Clark <robdclark@chromium.org>
Acked-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20660>

.gitlab-ci/meson/build.sh

@@ -61,6 +61,7 @@ esac
 rm -rf _build
 meson _build --native-file=native.file \
       --wrap-mode=nofallback \
+      --force-fallback-for perfetto \
       ${CROSS+--cross "$CROSS_FILE"} \
       -D prefix=`pwd`/install \
       -D libdir=lib \