RFR: 6562489: Font-Renderer should ignore invisible characters \u2062 and \u2063

[Daniel Gredler]

Expands regression test to cover bug JDK-6562489.

No additional fix is required after the JDK-8208377 fix (see #22670).

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Commit messages:
 - Expand regression test to cover bug 6562489

Changes: https://git.openjdk.org/jdk/pull/23547/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23547&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-6562489
  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23547.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23547/head:pull/23547

PR: https://git.openjdk.org/jdk/pull/23547