RFR: JDK-8273958: gtest/MetaspaceGtests executes unnecessary tests in debug builds

[Thomas Stuefe]

May I please have reviews for this trivial fix.

We miss two "debug==false" requires rules on tests meant for non-debug only. Taking them out reduces test runtime on debug by ~20 seconds.

I also shifted some of the existing requires tags down to cluster them together in one place, for better clarity.

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

Commit messages:
 - JDK-8273958-gtest-MetaspaceGtests-executes-unnecessary-tests-in-debug-builds

Changes: https://git.openjdk.java.net/jdk/pull/5571/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5571&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273958
  Stats: 10 lines in 1 file changed: 6 ins; 4 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5571.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5571/head:pull/5571

PR: https://git.openjdk.java.net/jdk/pull/5571