Support JDK 18

[sormuras]

As mentioned in #18465 (comment) an upgrade to ASM 9.2 is required to support scanning/parsing/reading classes compiled to Java 18.

[ice1000]

It's now a week before JDK 18 GA :)

[octylFractal]

Keeping track of the issues with console encoding (these stem from the console default charset no longer aligning with Charset.defaultCharset()):

• Need unicode output tests for the following:
  • TestKit
  • Test task
  • JVM metadata detection
  • GCC metadata detection
  • TODO find more places we capture console output with the default encoding.

Edit: see #20267 for more details. These items won't be fixed when this issue is closed.

[big-guy]

We still need to add JDK18 to compatibility guide, release notes and release features

[sormuras]

Fine!

Now, on to #20372

[danielpeintner]

We still need to add JDK18 to compatibility guide, release notes and release features

I think updates to Compatibility Matrix are still missing...
https://docs.gradle.org/current/userguide/compatibility.html

If you are aware of it and want to wait for the official 7.5 release it is fine..

[octylFractal]

I'm not sure what you mean, the code is updated (source), but that page isn't because it's 7.4.2, not the latest nightly. It seems like the nightly docs aren't updated because the nightly failed to build is not built yet, but the change is for sure in master already.

[danielpeintner]

What I meant was that the website is not yet showing the update but that might be because 7.5.x has not been officially published. Thanks!