Improve performance of icon loading in ImageUtilities

### Body

With NetBeans now containing [more SVG icons](https://github.com/apache/netbeans/pull/8083), and with more icons being [loaded](https://github.com/apache/netbeans/pull/8194) via ImageUtilities rather than alternative methods, it might be worth taking a look at the performance of ImageUtilities.getIcon, and see if there are possible optimizations that should be done. A first step, switching from Batik to JSVG, was [already done](https://github.com/apache/netbeans/pull/7941).

This issue is intended to continue the discussion that was started in [a comment](https://github.com/apache/netbeans/pull/8194#discussion_r1929834990) in another issue.

### Committer

- [x] I acknowledge that I am a maintainer/committer in the Apache NetBeans project.

Start with ImageUtilities.getIcon and review the performance discussion linked from this issue, including the earlier Batik-to-JSVG change and the referenced icon-loading pull requests. Determine whether a concrete optimization can be identified and define completion around a measurable improvement in icon-loading performance.

Written by the indexing model from the issue text.