RFR: 8264999: GeneralPath.lineTo() to itself produces jagged lines [v3]

[Jeremy]

On Fri, 10 Jun 2022 00:30:17 GMT, Jeremy <duke at openjdk.java.net> wrote:

>> Previously when you drew a line that moved exactly (+0, +0) with a miter stroke the Stroker class acted like a horizontal miter was appropriate. Now we abort instead, so no miter is applied.
>> 
>> The new unit test tests the original steps plus several variations.
>> 
>> I'm a little nervous about this change because it looks like someone previously considered this exact condition and implemented a different behavior. I don't think I understand the original rationale.
>
> Jeremy has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JDK-8264999: GeneralPath.lineTo() to itself produces jagged lines
>   
>   Separating "prev == DRAWING_OP_TO" condition per Laurent's code review.
>   
>   I also reorganized & commented on the unit test scenarios, including a few new commented out scenarios.

OK, the logic is revised as requested:

I also revised the failing scenarios (now commented out). I would be happy to discuss those further, but IMO those should not impede the resolution of this ticket.

(There is, yet again, a new disabled scenario that fails.)

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PR: https://git.openjdk.org/jdk/pull/8943