RFR: 7904110: IDEA plugin: Update plugin for new message format

[Jorn Vernee]

The JUnit output was updated to include a timestamp in https://github.com/openjdk/jtreg/commit/470718a0637fbfd9a883de66e7955a4c26e05760

This patch updates the parser in the idea plugin to be able to handle the timestamps.

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Commit messages:
 - Adapt JUnit result parser for timestamps in output

Changes: https://git.openjdk.org/jtreg/pull/300/files
  Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=300&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7904110
  Stats: 5 lines in 1 file changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jtreg/pull/300.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/300/head:pull/300

PR: https://git.openjdk.org/jtreg/pull/300