CI: Remove per-test-asan wrapper

Now that we've concluded the Xwayland/fontconfig stuff, we don't
actually need a per-test wrapper; we can just set the options globally.

It turns out that we don't need to set the options at all anyway, since
the previous commit adds the LSan suppressions to all test runs, and
LSan is enabled by default, so we can just bin it.

Signed-off-by: Daniel Stone <daniels@collabora.com>