Rollup merge of #146455 - cuviper:no-rustc-version, r=jieyouxu

test: remove an outdated normalization for rustc versions

These "you are using $RUSTC_VERSION" help messages were removed in
rust-lang/rust#142943, but rust-lang/rust#142681 started before that and
merged later, so its normalization is vestigial.

Author: Zalathar