Auto merge of #146328 - zetanumbers:fix-141951, r=lcnr

Skip typeck for items w/o their own typeck context

Skip items which forward typeck to their ancestor.

Should remove some potential but unnecessary typeck query waits, hence might improve performance for the parallel frontend.

Thanks to `@ywxt` for a fix suggestion

Fixes rust-lang/rust#141951

Author: bors