ci: Set LSAN_OPTIONS for tests

When running the testsuite with the address sanitizer,
many of our dependencies cause it to report cause it
to report memory leaks, causing tests to fail.
Therefore, point the leak sanitizer at a list of
suppressions. The list is kept in the lsan.supp
file in git.

.gitlab-ci/run-tests.sh

@@ -7,6 +7,9 @@ srcdir=$( pwd )
 builddir=$1
 backend=$2
 
+# Ignore memory leaks lower in dependencies
+export LSAN_OPTIONS=suppressions=$srcdir/lsan.supp
+
 case "${backend}" in
   x11)
     xvfb-run -a -s "-screen 0 1024x768x24" \