RFR: 8268534: some serviceability/jvmti tests should be run in driver mode

[Igor Ignatyev]

Hi all,

could you please review this small patch that switches execution mode in 4 `serviceability/jvmti` tests?
in all instances, the main test classes seem not to do actual testing and just orchestrate execution.

testing: `serviceability/jvmti`  on `{linux,windows,macosx}-x64`

Thanks,
-- Igor

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Commit messages:
 - copyright
 - 8268534

Changes: https://git.openjdk.java.net/jdk/pull/4454/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4454&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268534
  Stats: 7 lines in 4 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4454.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4454/head:pull/4454

PR: https://git.openjdk.java.net/jdk/pull/4454