[Rev 05] RFR: 6554: Support JFR in OpenJDK 8

[Marcus Hirt]

> This is for OpenJDK 8 implementations that have backported JFR, e.g. Azul's JDK. There is also a backport effort for OpenJDK 8 in general.

The pull request has been updated with 1 additional commit.

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Added commits:
 - 963d159c: Fixing tests and supporting vendor classification without JVMDescriptor

Changes:
  - all: https://git.openjdk.java.net/jmc/pull/19/files
  - new: https://git.openjdk.java.net/jmc/pull/19/files/017555a4..963d159c

Webrevs:
 - full: https://webrevs.openjdk.java.net/jmc/19/webrev.05
 - incr: https://webrevs.openjdk.java.net/jmc/19/webrev.04-05

  Stats: 49 lines in 3 files changed: 21 ins; 4 del; 24 mod
  Patch: https://git.openjdk.java.net/jmc/pull/19.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/19/head:pull/19

PR: https://git.openjdk.java.net/jmc/pull/19