RFR: 8371188: [s390x] Un-ProblemList TestUnreachableInnerLoop.java

[Amit Kumar]

Trivial change,
After [JDK-8288981](https://bugs.openjdk.org/browse/JDK-8288981) delivery test is now passing on s390x. So It can be removed from the problemlist.

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

Commit messages:
 - remove

Changes: https://git.openjdk.org/jdk/pull/28122/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28122&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8371188
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28122.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28122/head:pull/28122

PR: https://git.openjdk.org/jdk/pull/28122