[jdk11u-dev] RFR: 8213330: Fix legal headers in i18n tests

[Christoph Langer]

Backport of JDK-8213330. Change applies cleanly on files that exist in 11. Some don't so obviously those can't be changed.

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Commit messages:
 - Backport a1029a472983b457707f8807b160b7eaf4a123f9

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/340/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=340&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8213330
  Stats: 111 lines in 29 files changed: 0 ins; 58 del; 53 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/340.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/340/head:pull/340

PR: https://git.openjdk.java.net/jdk11u-dev/pull/340