RFR: 8337995: ZUtils::fill uses std::fill_n

[Kim Barrett]

Please review this change to zUtils.cpp to use a for-loop to fill a block of
memory rather than using the std::fill_n algorithm. Use of <algorithm> is
currently not permitted in HotSpot.

Testing: mach5 tier1

-------------

Commit messages:
 - zUtils remove <algorithm>

Changes: https://git.openjdk.org/jdk/pull/22667/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22667&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337995
  Stats: 6 lines in 1 file changed: 2 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/22667.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22667/head:pull/22667

PR: https://git.openjdk.org/jdk/pull/22667