Rollup merge of #143984 - JonathanBrouwer:fix-feature-gate-ice, r=Urgau

Fix ice for feature-gated `cfg` attributes applied to the crate

This PR fixes two fixes:
1. When a feature gated option of the `cfg` attribute is applied to the crate, an ICE would occur because features are not yet available at that stage. This is fixed by ignoring the feature gate at that point, the attribute will later be re-checked (this was already done) when the feature gate is available. Fixes rust-lang/rust#143977
2. Errors and lints on the `cfg` attribute applied to the crate would be produced twice, because of the re-checking. This is fixed by not producing any errors and lints during the first run.

The added regression test checks both problems.
r? ``@jdonszelmann``

Author: matthiaskrgr