[jdk11u-dev] RFR: 8257856: Make ClassFileVersionsTest.java robust to JDK version updates

[Christoph Langer]

I had to resolve to jdk11u, now the test is identical to upstream.

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Commit messages:
 - Backport 79aa7b15dbc54de891838ae2d4ca63838028c157

Changes: https://git.openjdk.org/jdk11u-dev/pull/1867/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1867&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8257856
  Stats: 47 lines in 1 file changed: 26 ins; 1 del; 20 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1867.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/1867/head:pull/1867

PR: https://git.openjdk.org/jdk11u-dev/pull/1867