<i18n dev> RFR: 6381945: (cal) Japanese calendar unit test system should avoid multiple static imports

[Justin Lu]

Within _test/jdk/java/util/Calendar/CalendarTestScripts/Symbol.java_

GregorianCalendar alone handles all the necessary imports, Calendar is not needed

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Commit messages:
 - Update copyright
 - Remove redundant import

Changes: https://git.openjdk.org/jdk/pull/11855/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11855&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-6381945
  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11855.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11855/head:pull/11855

PR: https://git.openjdk.org/jdk/pull/11855