RFR: JDK-8301077: Replace NULL with nullptr in share/services/

[Johan Sjölen]

Do the conversion in the share/services/ sub-directory and all of its files.

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Commit messages:
 - Manual fixes
 -  Replace NULL with nullptr in share/services/

Changes: https://git.openjdk.org/jdk/pull/12189/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12189&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301077
  Stats: 856 lines in 44 files changed: 0 ins; 0 del; 856 mod
  Patch: https://git.openjdk.org/jdk/pull/12189.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12189/head:pull/12189

PR: https://git.openjdk.org/jdk/pull/12189