added test for issue 1470

[georgRusanov]

What kind of change does this PR introduce?

test for issue 1470

[mandarini]

@georgRusanov can you please rebase the branch with latest master? Let me know when this is ready for review! Thank you!!!!

[georgRusanov]

@mandarini Hello
This and the next PRs are just examples for the issue 1470. They have the same test, but with different relatime-js versions.
They are show that with relatime-js older than 2.11.12 and without(unavailable or incompatible for some cloud environments) isows, realtimeClient will not be created, but it will be created with 2.11.12.
I don't think it should be merged. At least, this one will fail all the time while the issue exists. The second one will be closed in future.

[mandarini]

@georgRusanov once this is merged and released, the tests should be passing, and we can merge your PR. Thank you for adding those tests!