## Problem
The nightly test discovered problems in the extensions upgrade test.
1. `PLv8` has different versions on PGv17 and PGv16 and a different test
set, which was not implemented correctly
[sample](https://github.com/neondatabase/neon/actions/runs/13382330475/job/37372930271)
2. The same for `semver`
[sample](https://github.com/neondatabase/neon/actions/runs/13382330475/job/37372930017)
3. `pgtap` interfered with the other tests, e.g. tables, created by
other extensions caused the tests to fail.
## Summary of changes
The discovered problems were fixed.
1. The tests list for `PLv8` is now generated using the original
Makefile
2. The patches for `semver` are now split for PGv16 and PGv17.
3. `pgtap` is being tested in a separate database now.
---------
Co-authored-by: Mikhail Kot <mikhail@neon.tech>
## Problem
We run the compatibility tests only if we are upgrading the extension.
An accidental code change may break the test itself, so we have to check
this code as well.
## Summary of changes
The test is scheduled once a day to save time and resources.
---------
Co-authored-by: Alexander Bayandin <alexander@neon.tech>
## Problem
We have to test the extensions, shipped with Neon for compatibility
before the upgrade.
## Summary of changes
Added the test for compatibility with the upgraded extensions.
