RFR: 8342044: Increase timeout of gc/shenandoah/oom/TestClassLoaderLeak.java

[William Kemper]

Clean backport. Increase test timeout.

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Commit messages:
 - Backport 2c0c65353b2f67bdcd954b4d2c2ae3e9b24d1c22

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/131/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=131&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342044
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/131.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/131/head:pull/131

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/131