RFR: 8318364: Add an FFM-based implementation of harfbuzz OpenType layout

[Phil Race]

On Tue, 29 Aug 2023 22:04:40 GMT, Phil Race <prr at openjdk.org> wrote:

> 8318364: Add an FFM-based implementation of harfbuzz OpenType layout

I've added a test, which although it does not check the rendering is correct, it checks that the rendering would be identical in both the JNI and FFM cases. So if it's wrong it would already be wrong.
And the test covers multiple scripts and passes on all core platforms (macOS, Windows, Linux)
And I've separately manually verified that the rendering is as expected - if you have the fonts available.

At this point the code is ready for review for consideration for pushing to JDK 22.

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PR Comment: https://git.openjdk.org/jdk/pull/15476#issuecomment-1769241548
PR Comment: https://git.openjdk.org/jdk/pull/15476#issuecomment-1769244133