Auto merge of #116932 - Kobzol:fix-stage1-tests, r=Mark-Simulacrum

Fix x86_64-gnu-llvm-15 CI tests

The CI script was broken - if there was a test failure in the first command chain (inside the `if`), CI would not report the failure.

It happened because there were two command chains separated by `&&` in the script, and since `set -e` doesn't exit for chained commands, if the first chain has failed, the script would happily continue forward, ignoring any test failures.

This could be fixed e.g. by adding some `|| exit 1` to the first chain, but I suppose that the `&&` chaining is unnecessary here anyway.

Reported [on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/242791-t-infra/topic/test.20failure.20didn't.20stop.20CI).

Fixes: rust-lang/rust#116867