RFR: 8283467: runtime/Thread/StopAtExit.java needs updating

[Daniel D.Daugherty]

A small fix to convert the runtime/Thread/StopAtExit.java from using the
java.lang.Thread.stop() method to using the JVM/TI StopThread() method.

This fix has been tested with Mach5 Tier[134567] (upper tiers in process)
and StressWrapper_StopAtExit.java testing for 4 hours for each config {release,
fastdebug,slowdebug}. No failures and no memory leaks were observed.

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Commit messages:
 - 8283467.cr0

Changes: https://git.openjdk.java.net/jdk/pull/7910/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7910&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283467
  Stats: 106 lines in 2 files changed: 94 ins; 0 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7910.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7910/head:pull/7910

PR: https://git.openjdk.java.net/jdk/pull/7910