RFR: 8267565: Support "@1x" and "@3x" high-density image naming convention

[Kevin Rushforth]

On Fri, 22 Mar 2024 16:17:29 GMT, drmarmac <duke at openjdk.org> wrote:

> This PR extends the range of hi-res images that are loaded via naming convention, now including scale factors higher than `@2x`. 
> Supporting these is already being [recommended](https://developer.apple.com/design/human-interface-guidelines/images#Best-practices) for some platforms.
> 
> I tested this manually on Windows with "300%" UI scale factor, and verified `@2x` still works on macOS.

Reviewers: @kevinrushforth @lukostyra

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PR Comment: https://git.openjdk.org/jfx/pull/1429#issuecomment-2018650301