RFR: JDK-8300651: Replace NULL with nullptr in share/runtime/ [v2]

[Johan Sjölen]

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

Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:

  More manual fixes from DHolmes

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12094/files
  - new: https://git.openjdk.org/jdk/pull/12094/files/64d2c224..f71c64b7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12094&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12094&range=00-01

  Stats: 9 lines in 8 files changed: 0 ins; 2 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/12094.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12094/head:pull/12094

PR: https://git.openjdk.org/jdk/pull/12094