Now that the Terminal is doing a better job of actually marking which
lines were and were not wrapped, we're not always copying lines as
"wrapped" when they should be. We're more correctly marking lines as not
wrapped, when previously we'd leave them marked wrapped.
The real problem is here in the `ScrollFrame` method - we'd manually
newline the cursor to make the terminal's viewport shift down to a new
line. If we had to scroll the viewport for a _wrapped_ line, this would
cause the Terminal to mark that line as broken, because conpty would
emit an extra `\n` that didn't actually exist.
This more correctly implements `ScrollFrame`. Now, well move where we
"thought" the cursor was, so when we get to the next `PaintBufferLine`,
if the cursor needs to newline for the next line, it'll newline, but if
we're in the middle of a wrapped line, we'll just keep printing the
wrapped line.
A couple follow up bugs were found to be caused by the same bad logic.
See #5039 and #5161 for more details on the investigations there.
## References
* #4741 RwR, which probably made this worse
* #5122, which I branched off of
* #1245, #357 - a pair of other conpty wrapped lines bugs
* #5228 - A followup issue for this PR
## PR Checklist
* [x] Closes#5113
* [x] Closes#5180 (by fixing DECRST 25)
* [x] Closes#5039
* [x] Closes#5161 (by ensuring we only `removeSpaces` on the actual
bottom line)
* [x] I work here
* [x] Tests added/passed
* [n/a] Requires documentation to be updated
## Validation Steps Performed
* Checked the cases from #1245, #357 to validate that they still work
* Added more and more tests for these scenarios, and then I added MORE
tests
* The entire team played with this in selfhost builds
6fabc4abb7