RFR: 6588: Move JMC core to JDK 8 [v6]

[Marcus Hirt]

> Compromise that might be enough to make JMC 8 more enjoyable for people streaming. The grand end goal will be to get rid of StreamModel, but there is no time left for JMC 8. Might want to mark the toolkits as deprecated, and kill them off in a later release.

Marcus Hirt has updated the pull request incrementally with one additional commit since the last revision:

  Various minor fixes and removing unnecessary API

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Changes:
  - all: https://git.openjdk.java.net/jmc/pull/194/files
  - new: https://git.openjdk.java.net/jmc/pull/194/files/37616c85..a4a3d223

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=194&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=194&range=04-05

  Stats: 22 lines in 2 files changed: 1 ins; 20 del; 1 mod
  Patch: https://git.openjdk.java.net/jmc/pull/194.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/194/head:pull/194

PR: https://git.openjdk.java.net/jmc/pull/194