RFR: 8068: Move JMC 9 to JDK 17 [v5]

[Brice Dutheil]

> This PR builds atop #359 which has a number of improvement.
> * #359
> 
> It removed older platform that didn't support Java17 (see https://wiki.eclipse.org/Eclipse/Installation).
> 
> I didn't changed the agent to 17 though.

Brice Dutheil has updated the pull request incrementally with one additional commit since the last revision:

  Set up maven toolchains

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

Changes:
  - all: https://git.openjdk.org/jmc/pull/482/files
  - new: https://git.openjdk.org/jmc/pull/482/files/f3b9be91..4164d8af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=482&range=04
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=482&range=03-04

  Stats: 111 lines in 4 files changed: 91 ins; 5 del; 15 mod
  Patch: https://git.openjdk.org/jmc/pull/482.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/482/head:pull/482

PR: https://git.openjdk.org/jmc/pull/482