[jdk11u-dev] RFR: 8296084: javax/swing/JSpinner/4788637/bug4788637.java fails intermittently on a VM

[Goetz Lindenmaier]

I backport this for parity with 11.0.20-oracle.

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Commit messages:
 - Backport 2aaf3c5b01ddf5363eabfc6832133a2909fc27e3

Changes: https://git.openjdk.org/jdk11u-dev/pull/1996/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1996&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296084
  Stats: 29 lines in 1 file changed: 22 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1996.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/1996/head:pull/1996

PR: https://git.openjdk.org/jdk11u-dev/pull/1996