RFR: 8328862: Remove unused GrowableArrayFilterIterator

[Kim Barrett]

Please review this trivial removal of the unused GrowableArrayFilterIterator
class template.

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Commit messages:
 - remove unused GrowableArrayFilterIterator

Changes: https://git.openjdk.org/jdk/pull/18466/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18466&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328862
  Stats: 53 lines in 1 file changed: 0 ins; 52 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18466.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18466/head:pull/18466

PR: https://git.openjdk.org/jdk/pull/18466