RFR: 8286891: thread_local causes undefined symbol error with XL C

[Tyler Steele]

When using XLClang++ to compile a `thread_local` struct with a destructor, a compiler bug is exposed that results in a missing constructor and a linker error.

Adding the missing constructor solves this issue.
CHnges
- Builds on AIX (previously broken)

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Commit messages:
 - XL C compiler bug workaround

Changes: https://git.openjdk.java.net/jdk/pull/8754/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8754&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286891
  Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8754.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8754/head:pull/8754

PR: https://git.openjdk.java.net/jdk/pull/8754