minor #5267 Improve InstallViaComposerTest (sanmai)
minor #5267 Improve InstallViaComposerTest (sanmai)

This PR was merged into the 2.15 branch.

Discussion
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Improve InstallViaComposerTest

This PR:

- [x] Changes the test to clone only one level deep. This is faster.
- [x] Changes commit op to work without GPG signing. If it was configured on the system level, the commit will fail.

Extracted from #5262

Commits
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7657d9c64 Improve InstallViaComposerTest

gharlan/PHP-CS-Fixer,Slamdunk/PHP-CS-Fixer,keradus/PHP-CS-Fixer,kubawerlos/PHP-CS-Fixer,Slamdunk/PHP-CS-Fixer,kubawerlos/PHP-CS-Fixer,gharlan/PHP-CS-Fixer,FriendsOfPHP/PHP-CS-Fixer,FriendsOfPHP/PHP-CS-Fixer,keradus/PHP-CS-Fixer,SpacePossum/PHP-CS-Fixer,SpacePossum/PHP-CS-Fixer