RFR: JDK-8297413: Remove easy warnings in javafx.graphics [v2]

[John Hendrikx]

On Wed, 30 Nov 2022 12:48:10 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> If the casts in the numerator actually matter, then the cast in the denominator can be removed. The latter are the ones that Eclipse flags for me as unnecessary.
>
> I still think that any change here would be a very low value change. If done incorrectly, as it was in the initial attempt, it can introduce bugs. Even if done correctly, I see no point in it.

@kevinrushforth This has been mostly reverted, and is a lesson for me to not do more than what the warning suggests without checking very carefully. It just looked like a bunch of unnecessary casts, but it is has one edge case with negation overflow of a signed integer that I missed (whether it can happen in practice I did not analyze further).

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PR: https://git.openjdk.org/jfx/pull/960