RFR: 8273921: Refactor NSK/JDI tests to create thread using factory

[Leonid Mesnik]

8273921: Refactor NSK/JDI tests to create thread using factory

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Commit messages:
 - EventRequest
 - ExceptionRequest
 - ThreadStartRequest
 - ThreadReference
 - more tests
 - EventRequestManager
 - EventSet
 - fix
 - Event
 - StepRequest
 - ... and 12 more: https://git.openjdk.java.net/jdk/compare/e66bf472...24a5b21a

Changes: https://git.openjdk.java.net/jdk/pull/5515/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5515&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273921
  Stats: 1345 lines in 174 files changed: 103 ins; 242 del; 1000 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5515.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5515/head:pull/5515

PR: https://git.openjdk.java.net/jdk/pull/5515