RFR: 8269967: JavaFX should fail fast on macOS below minimum version

[Kevin Rushforth]

On Tue, 6 Jul 2021 23:54:12 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

> This PR implements a version check in the JavaFX runtime initialization code on macOS to ensure that the platform is running a version of macOS that is at or above the minimum version. If the platform is below the specified minimum, the JavaFX initialization code throws an exception.
> 
> The minimum version is passed from the `mac.gradle` file to the Mac glass code as a pair of build time constants, which are compared at runtime to the platform version.
> 
> Notes to reviewers:
> 
> * In case anyone is interested, the first commit has some debug logging which will print the minimum version and the detected platform version. I removed them with the second commit.

Alternatively, I could add a new JNI function to check the version, and call that right after the `loadLibrary`. That might be cleaner than doing it as part of `initIDs`

-------------

PR: https://git.openjdk.java.net/jfx/pull/567