Integrated: some test refactorings

[Vicente Romero]

Refactoring tests at UniversalTvarsCompilationTests

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

Commit messages:
 - test refactorings

Changes: https://git.openjdk.java.net/valhalla/pull/660/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=660&range=00
  Stats: 69 lines in 1 file changed: 8 ins; 39 del; 22 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/660.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/660/head:pull/660

PR: https://git.openjdk.java.net/valhalla/pull/660