RFR: 8325180: Rename jvmti_FollowRefObjects.h [v2]

[Kim Barrett]

> Please review this trivial change that renames the file
> test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_FollowRefObjects.h
> to jvmti_FollowRefObjects.hpp, and replaces uses of NULL in the file.
> 
> Testing: mach5 tier1

Kim Barrett has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'master' into jvmti_FollowRefObjects
 - rename NULLs in jvmti_FollwRefObjects.hpp
 - rename jvmti_FollowRefObjects.h

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17689/files
  - new: https://git.openjdk.org/jdk/pull/17689/files/2fd44e24..bf1835b3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17689&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17689&range=00-01

  Stats: 5673 lines in 180 files changed: 3451 ins; 1256 del; 966 mod
  Patch: https://git.openjdk.org/jdk/pull/17689.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17689/head:pull/17689

PR: https://git.openjdk.org/jdk/pull/17689