[jdk25u] RFR: 8365919: Replace currentTimeMillis with nanoTime in Stresser.java

[Tejal Wakchaure]

Tested Changes Locally for `test/hotspot/jtreg/vmTestbase/nsk`

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Commit messages:
 - Tejal Wakchaure
 - 8365919: Replace currentTimeMillis with nanoTime in Stresser.java

Changes: https://git.openjdk.org/jdk25u/pull/208/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u&pr=208&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365919
  Stats: 25 lines in 1 file changed: 6 ins; 6 del; 13 mod
  Patch: https://git.openjdk.org/jdk25u/pull/208.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/208/head:pull/208

PR: https://git.openjdk.org/jdk25u/pull/208