RFR: JDK-8294379: Missing comma after copyright year

[Alexandre Iline]

Adding comma missed in the original commit.

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Commit messages:
 - JDK-8294379: Missing comma after copyright year

Changes: https://git.openjdk.org/jdk/pull/10431/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10431&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294379
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10431.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10431/head:pull/10431

PR: https://git.openjdk.org/jdk/pull/10431