cabal v2-install ignores flag --run-tests

(I searched whether this issue is already reported, but couldn't find it. If it exists, please tag it with `cabal-install: cmd/install`.)

It seems like
```
cabal v2-install --run-tests
```
simply ignores the option `--run-tests`. Neither a test-suite is run nor a warning is emitted that this option isn't valid.
Seems like this hasn't been working for 5 years at least, judging from the discussion at https://stackoverflow.com/questions/33040790/how-do-i-run-the-tests-that-are-part-of-an-installed-installing-cabal-package#comment53903271_33041029.

I would find `cabal install --run-tests` useful because it would run the tests with the `sdist`-generated package, ensuring that all files needed by the testsuite are packaged up correctly. (One easily forgets adding test files to `extra-source-files` in the .cabal file.)

I think while this is not working as expected, `cabal` should issue a warning that the flag is ignored.

I am using a recent version of the development branch:
```
$ cabal --version
cabal-install version 3.5.0.0
compiled using version 3.5.0.0 of the Cabal library
```