RFR: 8357672: Extreme font sizes can cause font substitution

[Dmitry Markov]

On Wed, 28 May 2025 20:19:42 GMT, Phil Race <prr at openjdk.org> wrote:

> Instrumenting the existing ExtremeFontSizeTest.java, it was noted that the freetype code, when encountering a null return from getting a scaler context, would over-interpret this as a bad font.
> The test was intended to check this wasn't happening by verifying metrics before and after using extreme sizes.
> But the scenaro was not being detected by the test because a replacement font was substituted and it did not have zero metrics.
> So the updated test checks that the metrics before and after are the same.
> This new version of the test failed on Linux before the JDK source updates and passes afterwards.

Marked as reviewed by dmarkov (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/25511#pullrequestreview-2877798577