`--dev` implies it.

... in `follow_chain.rs` test, and also increase waiting time for node's
warm-up.

These tests used `assert_cmd::carg::cargo_bin`, which is deprecated.
It is meant to be replaced with the macro `assert_cmd::cargo_bin!`,
which required tests to be moved to the `cli` crate.
If tests hadn't been moved, that macro would fail to find the binary,
as the `CARGO_BIN_EXE_*` environment variable with the absolute path
to a binary target’s executable would not have been set.
Moving the tests causes it to be set, and the macro then works.

See https://doc.rust-lang.org/beta/cargo/reference/environment-variables.html

The previous commit added a `dev-dependencies` section to the root `Cargo.toml`,
which is not allowed.

Live mode works with either ws(s):// or http(s):// in --uri. The endpoint
is converted to HTTP for state download and to WS for block/header RPC.

This is a temporary workaround until frame-remote-externalities restores
proper WS transport support in a future release; see
paritytech/polkadot-sdk#10258,
paritytech/polkadot-sdk#10766, and
paritytech/polkadot-sdk#10779 .