RFR: 8324893: Rename JVMDITools.h

[Kim Barrett]

8324893: Rename JVMDITools.h

Please review this trivial change that renames the file
test/hotspot/jtreg/vmTestbase/nsk/share/JVMDITools.h to JVMDITools.hpp.  There
are no uses of NULL in this file to be fixed.

Testing: mach5 tier1

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Commit messages:
 - rename JVMDITools.h

Changes: https://git.openjdk.org/jdk/pull/17636/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17636&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324893
  Stats: 6 lines in 3 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17636.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17636/head:pull/17636

PR: https://git.openjdk.org/jdk/pull/17636