RFR: 8377427: Reduce substring allocations in Color.web(String, double) [v2]

[Michael Strauß]

On Fri, 13 Feb 2026 19:12:44 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> `CssNumberParser` parses "-0" correctly as -0, just like `Double.parseDouble()` currently does. The existing code in `Color` is unchanged.
>
> Since this file is testing the parser and not the CSS handling of negative zeros, I think we should test for the results if parsing "0.0" and "-0.0".
> 
> For example:
> 
> assertEquals(Double.valueOf(0.0), Double.valueOf(parseDouble("0.0"));
> assertEquals(Double.valueOf(-0.0), Double.valueOf(parseDouble("-0.0"));

We already test zeros specifically in `preserveNegativeZero()`.

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PR Review Comment: https://git.openjdk.org/jfx/pull/2069#discussion_r2806062562