Fix cursor invalidation when line renditions are used

[j4james]

Summary of the Pull Request

When the renderer calculates the invalidate region for the cursor, it
needs to take the line rendition into account. But it was using a
relative coordinate rather than absolute coordinate when looking up the
line rendition for the row, so the calculated region could easily be
incorrect.

With this PR we now use the line rendition that was already being cached
in the CursorOptions structure, so we avoid needing to look it up
anyway. Similarly I've replaced the IsCursorDoubleWidth lookup with
the value that was already cached in the CursorOptions structure.

Validation Steps Performed

I've confirmed that the test case in issue #17226 is now working as
expected.

PR Checklist

• Closes Cursor invalidation failing when line renditions are used #17226

[j4james]

I'm just assuming there wasn't a good reason not to use the cached CursorOptions properties. If there was, this PR is obviously no good and we'll need to fix #17226 in some other way.

[lhecker]

Ah, of course! I'm not sure why I missed this. I think this is correct: _invalidateCurrentCursor is supposed to invalidate the last cursor position _PaintFrame. If the line rendition changes, it still needs to invalidate as if the previous line rendition was active.

Thanks for fixing this!

[DHowett]

@lhecker we may want to define DO_NOT_USE variants of those functions inside the renderer like you did for the cooked read code, just to audit cases like this!