[jdk11u-dev] RFR: 8305421: Work around JDK-8305420 in CDSJDITest.java

[luchenlin]

I backport this for parity with 11.0.21-oracle.

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Commit messages:
 - Backport 9ce5fdc96262ac80c5a2ac2d51a149408d3d727a

Changes: https://git.openjdk.org/jdk11u-dev/pull/2029/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2029&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305421
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2029.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2029/head:pull/2029

PR: https://git.openjdk.org/jdk11u-dev/pull/2029