RFR: 8262080: vmTestbase/nsk/jdi/Event/request/request001/TestDescription.java failed with "ERROR: new event is not ThreadStartEvent"

[Alex Menkov]

The fix updates the test to skip ThreadStartEvent/ThreadDeathEvent from other threads

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Commit messages:
 - skip system thread start/death

Changes: https://git.openjdk.java.net/jdk/pull/2927/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2927&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262080
  Stats: 48 lines in 2 files changed: 44 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2927.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2927/head:pull/2927

PR: https://git.openjdk.java.net/jdk/pull/2927