RFR: 8353235: Test jdk/jfr/api/metadata/annotations/TestPeriod.java fails with IllegalArgumentException

[SendaoYan]

Hi all,

In test jdk/jfr/api/metadata/annotations/TestPeriod.java, the tested class `PeriodicEvent` extends `Event`, bug `Event` has three event types `enabled/stackTrace/threshold` by default. So we need to add `period` event type before test manually.

Change has been verified locally, test-fix only, no risk.

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Commit messages:
 - 8353235: Test jdk/jfr/api/metadata/annotations/TestPeriod.java fails with IllegalArgumentException

Changes: https://git.openjdk.org/jdk/pull/24320/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24320&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353235
  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24320.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24320/head:pull/24320

PR: https://git.openjdk.org/jdk/pull/24320