cleanup: Remove unused tests/e2e directory.
cleanup: Remove unused tests/e2e directory.

It is not used even by test-e2e.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulipchat.com>

zulip/zulip-desktop,zulip/zulip-desktop,zulip/zulip-desktop,zulip/zulip-desktop