dominoes: Add test case with separate three-domino loops (#1939)
dominoes: Add test case with separate three-domino loops (#1939)

* Add test 'separate three-domino loops' in dominoes

* Update exercises/dominoes/canonical-data.json

Co-authored-by: Erik Schierboom <6e321e24be838c7616721fdb824f9c65569cbfd8@hotmail.com>

Co-authored-by: mariohuq <0a31c0c6ec53c6baa2d7b327918539e5a87617bf@github.com>
Co-authored-by: Erik Schierboom <6e321e24be838c7616721fdb824f9c65569cbfd8@hotmail.com>
jmluy/x-common,jmluy/x-common,jmluy/x-common