Allow extracted semantics tests to run with and without yul.

[ekpyron]

The need for this came up in #6888 and #6909.
This is a quick and dirty solution which we can approve upon later, but which will allow us to continue with #6888 soon.

[ekpyron]

This let's us define compileViaYul: also, which lets the test be run with and without yul.

It's first run without yul as usual. In case of expectation mismatch isoltest will do the same as always and print an additional warning stating that the test has to pass via yul as well.
In case without yul passes, the test is re-run with yul. If that passes, everything's fine. If that fails, isoltest can update expectations as usual, but prints the additional error message stating that the same test did pass without yul.