RFR: 8071: Cleanup after latest refactorings [v2]

[Christoph Langer]

> After JMC-7308, test JVMCommandLineToolkitTest.java should move into core/common.
> Also, there are some Javadoc related warnings during core build which should be fixed.

Christoph Langer has updated the pull request incrementally with one additional commit since the last revision:

  Spotless

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Changes:
  - all: https://git.openjdk.org/jmc/pull/485/files
  - new: https://git.openjdk.org/jmc/pull/485/files/2049937d..4996a29e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=485&range=01
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=485&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jmc/pull/485.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/485/head:pull/485

PR: https://git.openjdk.org/jmc/pull/485