RFR: 8293592: Remove JVM_StopThread, stillborn, and related cleanup [v2]

[David Holmes]

> Now that Thread.stop has been degraded to throw `UnsupportedOperationException` (JDK-8299610) the only direct source of async exceptions is from JVMTI `StopThread`. We can remove the `JVM_StopThread` code, remove the `stillborn` field from `java.lang.Thread` and its associated accesses from the VM, and we can stop special-casing `ThreadDeath` handling (as was done for the JDK code as part of JDK-8299610).
> 
> Note that JVMTI `StopThread` can only act on a thread that is alive, so it is no longer possible to stop a thread before it has been started.
> 
> Also note that there is a change in behaviour for JNI `ExceptionDescribe` as it no longer ignores `ThreadDeath` exceptions (not that it was ever specified to ignore them, it simply mirrored the behaviour of the default `UncaughtExceptionHandler` in `java.lang.ThreadGroup` - which also no longer ignores them so the mirroring behaviour remains the same).
> 
> Testing: tiers 1-3

David Holmes has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 16 commits:

 - Merge branch 'master' into 8293592-JVM_StopThread
 - Removal all special handling of ThreadDeath.
 - Remove all references to the stillborn field
 - Initial commit: remove JVM_StopThread
 - Merge
 - Updates to Java Thread Primitive Deprecation page
 - Repalce "it" with "victim thread"
 - Merge
 - Revert test/langtools/ProblemList.txt as jshell tests no longer rely on Thread.stop
 - become -> became in javadoc
 - ... and 6 more: https://git.openjdk.org/jdk/compare/3675f4c2...4eb07903

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Changes: https://git.openjdk.org/jdk/pull/10400/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10400&range=01
  Stats: 208 lines in 18 files changed: 19 ins; 146 del; 43 mod
  Patch: https://git.openjdk.org/jdk/pull/10400.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10400/head:pull/10400

PR: https://git.openjdk.org/jdk/pull/10400