Avoid using 'http://localhost/foo-cropped.png' in tests

[danielbachhuber]

Two image header tests use a http://localhost/foo-cropped.png value:

• Tests_Image_Header::test_create_attachment_object
• Tests_Image_Header::test_insert_cropped_attachment

In some system configurations, this can cause ImageMagick to throw an exception:

ImagickException: getimagesize(http://localhost/foo-cropped.png): failed to open stream: Connection refused

This was originally added in r27847. In skimming through #21785, it doesn't appear to be a deliberate decision to use http://localhost/foo-cropped.png. It would be better to use a value that doesn't trigger an outbound HTTP request.

[danielbachhuber]

41216.1.diff updates the tests to use foo-cropped.png instead of http://localhost/foo-cropped.php, and corrects the order of arguments passed to assertions.

[desrosj]

Passing build with patch: ​https://travis-ci.org/desrosj/wordpress-develop/builds/248936584

[SergeyBiryukov]

In 41016:

Media: Correct the order of arguments passed to assertions in Tests_Image_Header.

Props danielbachhuber.
See #41216.

[SergeyBiryukov]

I think the GUID should remain a URL, otherwise it gets sanitized to an invalid URL: http://foo-cropped.png.

[SergeyBiryukov]

In 41017:

Media: Use a filename instead of a URL in image header tests to avoid triggering an outbound HTTP request causing an ImageMagick exception on some configurations.

Props danielbachhuber.
Fixes #41216.

[ocean90]

#36589 was marked as a duplicate.