[lldb] Disable some tests on windows

This patch skips both `test_completion_target_create_from_root_dir`
introduced in `e8966125` and  `target-label.test` introduced in `1e82b201

`
since I don't have a windows machine to try to accomodate the filesystem
path style differences for these tests to pass.

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>