virtme-scripts: Add LSAN_OPTION

In preparation of turning mem leak detection on in CI, this patch adds
LSAN_OPTIONS to be able to pass the suppression file.

This *does not* turn the mem leak detection on yet, as we still
need some additional mem leak fixes.

This removes fast unwind set to zero as well, as that will add a massive
runtime penalty to some of our tests, and we'll no longer need it as
we've included the entire libfontconfig as a mem leak source in the
suppression file.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>

.gitlab-ci/virtme-scripts/per-test-asan.sh

@@ -1,20 +1,6 @@
 #!/bin/bash
 
-# When running Debian's Xwayland and fontconfig, we hit memory leaks which
-# aren't visible on other setups. We do have suppressions for these tests, but
-# regrettably ASan can't see through omitted frame pointers in Expat, so for
-# Xwayland specifically, we disable fast-unwind.
-#
-# Doing it globally makes the other tests far, far, too slow to run.
-case "$1" in
-  *xwayland*)
-    export ASAN_OPTIONS="detect_leaks=0,fast_unwind_on_malloc=0"
-    ;;
-  *)
-    export ASAN_OPTIONS="detect_leaks=0"
-    ;;
-esac
-
-export ASAN_OPTIONS
+export LSAN_OPTIONS="suppressions=../.gitlab-ci/leak-sanitizer.supp"
+export ASAN_OPTIONS="detect_leaks=0"
 
 exec "$@"