TT#111150 add extra runtime options for unit tests

UBSAN doesn't print stack traces by default. Enable them.

The GLib slice allocator must be disabled for proper leak checks and
must be instructed to always use malloc instead.

Change-Id: Ic4fe5ad38aa4460fbe43858b97226cce7d658038

.github/workflows/unit-tests.yml

@@ -24,4 +24,4 @@ jobs:
 
       - name: Run unit tests with sanitizers enabled
         run: |
-          CFLAGS="$FLAGS" LDFLAGS="$FLAGS" ASAN_OPTIONS=verify_asan_link_order=0 make check
+          CFLAGS="$FLAGS" LDFLAGS="$FLAGS" ASAN_OPTIONS=verify_asan_link_order=0 UBSAN_OPTIONS=print_stacktrace=1 G_SLICE=always-malloc make check