Make git remote failure clearer in make_remote_config_repos

Starting in Git 2.51.0, at least one of the `git remote` commands
in the `make_remote_config_repos.sh` fixutre script fails, which
causes a subsequently run command depending on it to fail. This is
the cause of the CI failures observed in #2130.

But when any command fails, the intention is that the script fails
fast. To help achieve this, `set -e` is used. But the rules for
`set -e` have a number of exceptions. At least in some versions of
`bash`, the way `&&` was being used kept it from failing fast.

This changes that to run the commands separately, surfacing the
specific `git remote` command that fails, rather than a subsequent
command that fails later as a result of the first failure.

Author: EliahKagan

gix/tests/fixtures/make_remote_config_repos.sh

@@ -134,9 +134,14 @@ EOF
 
 git clone fetch multiple-remotes
 (cd multiple-remotes
-  git remote add other ../fetch && git fetch other
-  git remote add with/two/slashes ../fetch && git fetch with/two/slashes
-  git remote add with/two ../fetch && git fetch with/two
+  git remote add other ../fetch
+  git fetch other
+
+  git remote add with/two/slashes ../fetch
+  git fetch with/two/slashes
+
+  git remote add with/two ../fetch
+  git fetch with/two
 
   # add a specialised refspec mapping
   git config --add remote.with/two.fetch +refs/heads/special:refs/remotes/with/two/special
@@ -146,4 +151,4 @@ git clone fetch multiple-remotes
   git checkout -b track-special with/two/special
   git checkout -b main --track origin/main
   git checkout -b other-main --track other/main
-)
+)