Update image-circular-tests.el

Update image-circular-tests.el

* test/manual/image-circular-tests.el
(image-test-duplicate-keywords): Skip unless images are supported.
(image-test-circular-plist, image-test-:type-property-value): Ditto.
Wrap only failing forms in should[-error] rather than entire test
bodies.  Use simpler printed notation in place of function calls.
(image-test-circular-specs): Ditto.  Wrap overly wide docstring.
Mark as failing since shortly after its introduction (bug#36403#63).