RFR: JDK-8276046: codestrings.validate_vm gtest fails on ppc64, s390

[Thomas Stuefe]

Trivial patch to switch off the associated gtest on these platforms. PPC64 and s390 compilers don't use code strings.

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

Commit messages:
 - disable codestrings gtest on s390, ppc

Changes: https://git.openjdk.java.net/jdk/pull/6133/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6133&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276046
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6133.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6133/head:pull/6133

PR: https://git.openjdk.java.net/jdk/pull/6133