RFR: 8400: Add more show options for JMX Console graphs [v2]

[Marcus Hirt]

> Also cleaning up a little bit. There were some assumptions around the default XY chart that should be put in code etc.

Marcus Hirt 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/652/files
  - new: https://git.openjdk.org/jmc/pull/652/files/83fa46d6..8cb62f9b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=652&range=01
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=652&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jmc/pull/652.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/652/head:pull/652

PR: https://git.openjdk.org/jmc/pull/652