Unrolled build for rust-lang#127839

Rollup merge of rust-lang#127839 - ehuss:safe-directory-docker, r=Mark-Simulacrum

Fix git safe-directory path for docker images

This fixes the path for configuring the git safe.directory setting inside docker images. AFAIK, `~/gitconfig` without a dot is not something that git uses ([ref](https://git-scm.com/docs/git-config)). This was needed in my environment to avoid the ` fatal: detected dubious ownership in repository at '/checkout'` error. For context, this was added in rust-lang#99967.

src/ci/run.sh

@@ -19,7 +19,7 @@ if [ "$NO_CHANGE_USER" = "" ]; then
  # already be running with the right user.
  #
  # For NO_CHANGE_USER done in the small number of Dockerfiles affected.
- echo -e '[safe]\n\tdirectory = *' > /home/user/gitconfig
+ echo -e '[safe]\n\tdirectory = *' > /home/user/.gitconfig
 
  exec su --preserve-environment -c "env PATH=$PATH \"$0\"" user
  fi