Auto merge of #87737 - LeSeulArtichaut:unsafeck-less-freeze, r=oli-obk
Auto merge of #87737 - LeSeulArtichaut:unsafeck-less-freeze, r=oli-obk

Only compute `is_freeze` for layout-constrained ADTs

Places are usually shallow and quick to visit. By contrast, computing `is_freeze` can be much costlier, involving inference and trait solving. Making sure to call `is_freeze` only when necessary should be beneficial for performance in most cases.

See [this comparison](https://perf.rust-lang.org/compare.html?start=81f08a4763e7537b92506fa5a597e6bf774d20cc&end=56a58d347b1c7dd0c2984b8fc3930c408e26fbc2&stat=instructions%3Au) from #87710.

r? `@oli-obk`

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust