RFR: 8255330: gtest/MetaspaceGtests.java fail on 32-bit platforms

[Aleksey Shipilev]

Seems fairly trivial: `UseCompressedKlassPointers` is only available on 64-bit platforms.

Attention @tstuefe ;)

Testing:
 - [x] Affected test on Linux x86_64
 - [x] Affected test on Linux x86_32

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

Commit messages:
 - 8255330: gtest/MetaspaceGtests.java fail on 32-bit platforms

Changes: https://git.openjdk.java.net/jdk/pull/831/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=831&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255330
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/831.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/831/head:pull/831

PR: https://git.openjdk.java.net/jdk/pull/831