Auto merge of #142235 - Kobzol:rustc-dist-alt-assertions, r=marcoieni

Build rustc with assertions in `dist-alt` jobs

Revival of rust-lang/rust#131077, to check CI times now that we don't do PGO/BOLT anymore on Linux `-alt` builds.

r? `@ghost`

try-job: dist-x86_64-msvc-alt
try-job: dist-x86_64-linux-alt

Author: bors