[jdk11u-dev] RFR: 8251166: Add automated testcases for changes done in JDK-8214112

[Aleksey Shipilev]

Clean backport.

Additional testing:
 - [x] New tests pass on Linux/GTK3

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Commit messages:
 - Backport a0d6a8a1741489103d8448a1cd33626b6ac39cc9

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/237/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=237&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8251166
  Stats: 469 lines in 3 files changed: 469 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/237.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/237/head:pull/237

PR: https://git.openjdk.java.net/jdk11u-dev/pull/237