[jdk11u] RFR: 8338139: {ClassLoading, Memory}MXBean::isVerbose methods are inconsistent with their setVerbose methods

[Goetz Lindenmaier]

I backport this from 17.  I had hoped it would be clean, but I had to adapt the nullptr literals in the .cpp files.

Also, I had to resolve the copyright in all four hotspot files.

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Commit messages:
 - Backport 897f433b33a46d56cc6972b1c6b4405ecaa4dea9

Changes: https://git.openjdk.org/jdk11u/pull/94/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk11u&pr=94&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338139
  Stats: 204 lines in 6 files changed: 198 ins; 2 del; 4 mod
  Patch: https://git.openjdk.org/jdk11u/pull/94.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u.git pull/94/head:pull/94

PR: https://git.openjdk.org/jdk11u/pull/94