How to suppress "unsupported 'ghc' version detected" in test outputs?

It would be nice to be able to try out tests with unsupported `ghc` versions. Is there a way to suppress the "unsupported 'ghc' version detected" warning that is causing this diff?

From https://github.com/haskell/cabal/pull/9268#issuecomment-1845434668

```diff
diff --git a/cabal-testsuite/PackageTests/WarnEarlyOverwrite/dirty-install.out b/cabal-testsuite/PackageTests/WarnEarlyOverwrite/dirty-install.out
index 3a813eebf..34d3ad6eb 100644
--- a/cabal-testsuite/PackageTests/WarnEarlyOverwrite/dirty-install.out
+++ b/cabal-testsuite/PackageTests/WarnEarlyOverwrite/dirty-install.out
@@ -1,5 +1,6 @@
# cabal v2-install
Wrote tarball sdist to /dirty-install.dist/work/./dist/sdist/WarnEarlyOverwrite-0.1.0.0.tar.gz
+Warning: Unknown/unsupported 'ghc' version detected (Cabal 3.11.0.0 supports 'ghc' version < 9.8): /.../.ghcup/bin/ghc is version
Resolving dependencies...
Build profile: -w ghc- -O1
In order, the following will be built:
@@ -8,6 +9,7 @@ Error: [Cabal-7149]
Path '/warn-early-overwrite' already exists. Use --overwrite-policy=always to overwrite.
# cabal v2-install
Wrote tarball sdist to /dirty-install.dist/work/./dist/sdist/WarnEarlyOverwrite-0.1.0.0.tar.gz
+Warning: Unknown/unsupported 'ghc' version detected (Cabal 3.11.0.0 supports 'ghc' version < 9.8): /.../.ghcup/bin/ghc is version
Resolving dependencies...
Build profile: -w ghc- -O1
In order, the following will be built:
```