Integrated: JDK-8268908: Update test/jdk/valhalla/valuetypes tests to prepare for jtreg 6 and other clean up

[Mandy Chung]

Update test/jdk/valhalla/valuetypes tests to prepare for jtreg 6. Also rename references to the term "inline" to "primitive". some test case reorganization.

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Commit messages:
 - JDK-8268908: Update test/jdk/valhalla/valuetypes tests to prepare for jtreg 6 and other clean up

Changes: https://git.openjdk.java.net/valhalla/pull/447/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=447&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268908
  Stats: 1857 lines in 22 files changed: 746 ins; 841 del; 270 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/447.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/447/head:pull/447

PR: https://git.openjdk.java.net/valhalla/pull/447