Flag inner Thread methods for JDK 19 and greater

[Badbond]

Since JDK19, java.lang.Thread's methods have changed to support virtual threads. Specifically, for non-virtual threads, sleep(long) invokes sleep0(long) and yield() invokes yield0(). Moreover, since JDK21, sleep(long, int) and sleep(Duration) directly call sleep0(long) as opposed to sleep(long).

Now, to identify all blocking java.lang.Thread calls, BlockHound will flag invocations of sleep0(long) and yield0() as opposed to sleep(long) and yield() when running on JDK19 or greater.

Fixes #394.

[Badbond]

Verified against our codebase using ./gradlew --no-daemon -Pversion=1.0.9.BUILD-SNAPSHOT publishToMavenLocal. Note, this does change the method to instrument for JDK19 or greater, causing the error message to be different.

Also, as opposed to what was discussed in #394, the change now target JDK19+ as opposed to JDK21+. This is because the sleep0 and yield0 methods were already introduced back then. It felt more natural to already support it from that moment on, given the 0 suffixed methods are smaller in scope and will not be used by virtual threads.

Lastly, based on the contribution guidelines, I updated the license headers for changed files.

[pderop]

@Badbond ,

Thanks for the PR and thanks for following our contribution guidelines diligently.
Truly appreciate your attention to details, however, we should maintain the current license headers due to internal reasons.

Could you then please revert the changes related to license headers and keep the copyright unchanged ?
After that, then let's merge this PR !

thanks.

[Badbond]

Surely! Reverted the commit.

[pderop]

@Badbond , thanks for the PR !
LGTM