Auto merge of #113519 - SparrowLii:parallel_typeck, r=cjgillot

typeck in parallel

#108118 caused `typeck` to be transferred to the serial part (`check_unused`), which made the performance of parallel rustc significantly reduced.

This pr re-parallelize this part, which increases the average performance improvement of parallel rustc in `full` and `incr-full` scenarios from [14.4%](rust-lang/rust#110284 (comment)) to [23.2%](rust-lang/rust#110284 (comment)).

r? `@cjgillot`
cc `@oli-obk` `@Zoxc`

Author: bors