[jdk17u-dev] RFR: 8293177: Verify version numbers in legal files

[Goetz Lindenmaier]

I backport this for parity with 17.0.9-oracle.

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Commit messages:
 - Backport 69ede5baeda6645aa3e961a02cbd40db965fc6a1

Changes: https://git.openjdk.org/jdk17u-dev/pull/1620/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1620&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293177
  Stats: 153 lines in 1 file changed: 153 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1620.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1620/head:pull/1620

PR: https://git.openjdk.org/jdk17u-dev/pull/1620