RFR: 8290527: Bump macOS GitHub actions to macOS 11

[Ambarish Rapte]

On Fri, 22 Jul 2022 12:23:47 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

> Use macOS 11 / Xcode 12.4 for GitHub actions runs.
> 
> As noted in the JBS bug, macOS 10.15 has been deprecated as a GitHub Actions platform, and will be removed completely on August 30th. See https://github.com/actions/virtual-environments#available-environments and actions/virtual-environments#5583 for context.
> 
> This PR also switches to using XCode 12.4, which matches our production builds.
> 
> As you can see from the GHA run, the tests pass after this change.

Looks good. The GHA ran successfully.

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Marked as reviewed by arapte (Reviewer).

PR: https://git.openjdk.org/jfx/pull/844