testsuite: skipifVersion "9.6.3" in VersionPriority tests looks overfitted

The `VersionPriority` tests have code along the lines of

```
8832b2689a (Phil de Joux 2023-12-31 08:52:34 -0500 11) skipIfGhcVersion "== 9.6.3"
````

but the reason seems to be an unrelated bug in the testsuite:

```
8832b2689a (Phil de Joux 2023-12-31 08:52:34 -0500 8) -- To avoid this diff:
8832b2689a (Phil de Joux 2023-12-31 08:52:34 -0500 9) -- -Build profile: -w ghc-9.6.3 -O1
8832b2689a (Phil de Joux 2023-12-31 08:52:34 -0500 10) -- +Build profile: -w ghc- -O1
```

This kind of bug happens in situations where you build `cabal-tests` with a different `ghc` version to the one on your path I think, in any case, that is the bug which should be fixed rather than workarounds which only apply to very specific cases in the testsuite.

cc @philderbeast