Updated HtmlUnit to pick up the fixes for Neko #148

[rschwietzke]

Required changes to fix the shared-by-accident problem within Neko HTMLELements and the use in HtmlUnitNekoDOMBuilder

[rbri]

@rschwietzke hope the current impl is now correct and the performance is comparable to the last version.

Have tried again to get an idea about the performance comparison between the last release and the current code

https://raw.githubusercontent.com/HtmlUnit/htmlunit-jmh-benchmarks/refs/heads/main/src/main/java/org/htmlunit/jmh/benchmarks/htmlunit/HtmlParserBenchmark.md

have added another real huge html file - html-standard.html

Looks like the performance with and without cache is similar, i think we should stay with the cache and hope for further good ideas to improve the whole thing.

[rschwietzke]

I will revist the benchmark later this week and use my machine for comparison.