RFR: 8301549: Fix comment about ClassCircularityError

[Coleen Phillimore]

Please review this trivial change to fix this comment.

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Commit messages:
 - 8301549: Fix comment about ClassCircularityError

Changes: https://git.openjdk.org/jdk/pull/12344/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12344&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301549
  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12344.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12344/head:pull/12344

PR: https://git.openjdk.org/jdk/pull/12344