added test cases and removed test cases that no longer apply (the number of digits in PRs are no longer in the code)

making the tests happy

In D9257#210616, @PiRK wrote:

Ok wigh core-gui. But something need to be done about the automatic " PRxxxx to URL" conversion.

yea this ain't worth it

we need to come up with a standard notation to ease automation of tagging the done backports in the bitcoin-core/gui repo, what about using Backport of core-gui PRxxxxxx?

couldn't reproduce with for i in {1..100}; do ninja check-bitcoin-coinselector_tests; done, rebasing

this should probably be the last step once all of cashtab is proper React'd

addressed comments

@bot build-tsan

rebase on top of D9191

tested locally, looks good

update release notes

update for ecash

*ecash