libsysprof-analyze: add overlay mountinfo parsing test

This just ensures that we can parse the contents of the superblock options
that we get for "overlay" mounts via toolbox/podman. These still need to
be handled from SysprofMountNamespace when translating though.

Additionally, this stuff seems very brittle for parsing, unless it is
getting escaped somewhere I'm missing currently.

src/libsysprof-analyze/tests/meson.build

@@ -17,6 +17,7 @@ libsysprof_analyze_testsuite = {
   'test-list-counters'       : {'skip': true},
   'test-list-files'          : {'skip': true},
   'test-list-jitmap'         : {'skip': true},
+  'test-list-overlays'       : {'skip': true},
   'test-print-file'          : {'skip': true},
   'test-list-processes'      : {'skip': true},
   'test-list-address-layout' : {'skip': true},