RFR: 6996: Properly support converters [v8]

[Marcus Hirt]

> Including simple test to verify that the resulting instrumented methods are ok.

Marcus Hirt has updated the pull request incrementally with two additional commits since the last revision:

 - Formatting
 - Excluding abstract and interface methods

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Changes:
  - all: https://git.openjdk.java.net/jmc/pull/168/files
  - new: https://git.openjdk.java.net/jmc/pull/168/files/3ffaa3ec..b0de6925

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=168&range=07
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=168&range=06-07

  Stats: 9 lines in 2 files changed: 6 ins; 1 del; 2 mod
  Patch: https://git.openjdk.java.net/jmc/pull/168.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/168/head:pull/168

PR: https://git.openjdk.java.net/jmc/pull/168