spec: Fix Gitaly startup issues and update failure message

* Use a full path in Gitaly's `bin_dir` config to ensure the bundled
  Git symlink can link to the test binaries.

* Fix a regression in the `ci?` check that was introduced in
  https://gitlab.com/gitlab-org/gitlab/-/merge_requests/78061.

lib/gitlab/setup_helper.rb

@@ -130,7 +130,7 @@ module Gitlab
 
           config[:'gitaly-ruby'] = { dir: File.join(gitaly_dir, 'ruby') } if gitaly_ruby
           config[:'gitlab-shell'] = { dir: Gitlab.config.gitlab_shell.path }
-          config[:bin_dir] = File.join(gitaly_dir, '_build', 'bin') # binaries by default are in `_build/bin`
+          config[:bin_dir] = File.expand_path(File.join(gitaly_dir, '_build', 'bin')) # binaries by default are in `_build/bin`
           config[:gitlab] = { url: Gitlab.config.gitlab.url }
           config[:logging] = { dir: Rails.root.join('log').to_s }
 

spec/support/helpers/gitaly_setup.rb

@@ -327,8 +327,8 @@ module GitalySetup
 
     message += "\nCheck log/gitaly-test.log for errors.\n"
 
-    unless ci?
-      message += "\nIf binaries are missing, try running `make -C tmp/tests/gitaly build git.`\n"
+    unless ENV['CI']
+      message += "\nIf binaries are missing, try running `make -C tmp/tests/gitaly all WITH_BUNDLED_GIT=YesPlease`.\n"
       message += "\nOtherwise, try running `rm -rf #{tmp_tests_gitaly_dir}`."
     end