Rollup merge of rust-lang#148880 - yotamofek:pr/dockerfile-eslint-install, r=Kobzol,GuillaumeGomez

Remove explicit install of `eslint` inside of `tidy`'s Dockerfile

`tidy` will already install it (when needed) due to it being in `package.json`

With this change, we don't have the version of `eslint` specific in two different places :)

(this was added in rust-lang#141705 , before `tidy` gained the ability to run `npm install`, and is not needed anymore)

Author: Zalathar

src/ci/docker/host-x86_64/tidy/Dockerfile

@@ -28,9 +28,6 @@ COPY scripts/nodejs.sh /scripts/
 RUN sh /scripts/nodejs.sh /node
 ENV PATH="/node/bin:${PATH}"
 
-# Install eslint
-COPY host-x86_64/tidy/eslint.version /tmp/
-
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
@@ -40,8 +37,6 @@ RUN pip3 install --no-deps --no-cache-dir --require-hashes -r /tmp/reuse-require
 
 COPY host-x86_64/pr-check-1/validate-toolstate.sh /scripts/
 
-RUN bash -c 'npm install -g eslint@$(cat /tmp/eslint.version)'
-
 # NOTE: intentionally uses python2 for x.py so we can test it still works.
 # validate-toolstate only runs in our CI, so it's ok for it to only support python3.
 ENV SCRIPT TIDY_PRINT_DIFF=1 python2.7 ../x.py test \