Auto merge of #135023 - jieyouxu:boop, r=onur-ozkan

bootstrap: flip `compile::Rustc` vs `compile::Assemble`

The `PathSet` prefix matching unfortunately also has implications for `./x build compiler --stage 0`, because the path filter `"compiler"` gets consumed by `compile::Rustc` step first after `PathSet` prefix matching, whereas before `PathSet` prefix matching, `compile::Rustc` would not have consumed `"compiler"`.

This merely papers over #134970 to unblock contributors from using `./x build compiler --stage 0`.

The `PathSet` prefix matching behavior is tracked in #135022.

Closes #134970.