RFR: 8283651: nsk/jvmti/SuspendThread/suspendthrd003 may leak native memory

[Daniel D.Daugherty]

A trivial fix to nsk_jvmti_threadByName() to solve a native memory leak.

This fix has been stress tested with my StressWrapper60M_NMT_detail_suspendthrd003.java
test and I did NMT detailed monitoring for the whole 60M run. Total committed memory has
gone down from 1.17GB to 300MB. Prior to my last rebase, it was down to 239MB.

I ran the fix thru Mach5 Tier[1-7] with no failures. I just rebased the fix to the latest jdk/jdk
and Mach5 Tier[1-3] have passed with no failures. Tier[45] are still running.

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

Commit messages:
 - 8283651.cr0

Changes: https://git.openjdk.java.net/jdk/pull/8609/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8609&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283651
  Stats: 7 lines in 1 file changed: 6 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8609.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8609/head:pull/8609

PR: https://git.openjdk.java.net/jdk/pull/8609