Tests/DAL: add migration test checking Nextnet issue
What
Add a migration test checking the Nextnet issue, fixed in !16623 (merged). It thus addresses one item in #7741 (closed).
It also re-enables the migration tests to Alpha which were disabled in !16467 (a04cd9b4).
It also enables migration tests to Next, because that's where the issue was.
It also disables the history RPC migration test which fails for both migrations.
Why
To be sure the issue is corrected and there will be regression.
Edited by Eugen Zalinescu