test: Refactor tests using restart_node #19350

fixes #19345

This PR replaces consecutive calls to stop_node() and start_node() with restart_node() where appropriate in the functional tests.

The commit messages are repetitive but focused on each file changed with the intention of squashing if applicable.

There are less than 25 occurrences, so instead of 13 commits, I think this could be a single commit

There are less than 25 occurrences, so instead of 13 commits, I think this could be a single commit

Thanks, I'll squash them

<!--e57a25ab6845829454e8d69fc972939a-->

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

<!--174a7506f384e20aa4161008e828411d-->

Conflicts

Reviewers, this pull request conflicts with the following ones:

• #19013 (test: add v0.20.0 to backwards compatibility test by Sjors)
• #18554 (wallet: ensure wallet files are not reused across chains by mrwhythat)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

Checked (with git grep -C3 stop_node\() that none of the remaining uses of stop_node(x) is trivially followed by start_node(x). ACK 20b6e959449d0c07639599b99ba917d2cac62493