[css-break] monolithic-overflow-00[12].tentative.html are wrong

I think the tests named monolithic-overflow-001.tentative.html and monolithic-overflow-002.tentative.html (there are several of them) are wrong. They assume that a monolithic box cannot be split across columns and must therefore overflow them, but in fact they can be split -- they can't be "fragmented" at a proper break point, but the UA is allowed to slice them so that they don't overflow the fragmentation container.

Finally, if there are no possible break points below the top of the fragmentainer, and not all the content fits, the UA may break anywhere in order to avoid losing content off the edge of the fragmentainer. In such cases, the UA may also fragment the contents of monolithic elements by slicing the element’s graphical representation.

Commit that added them: https://github.com/web-platform-tests/wpt/commit/a2c3d90657a9d510fc80ded0b4c0317e86c3dfa8