RFR: 7439: Add methods in IParserExtension for Constant Pools

[Jean-Philippe Bempel]

Add extension methods when constants are read, referenced, resolved
and constant pools fully resolved to be able for example:

 * track constant pool usage inside events
 * replace or translate symbols, method names, etc... like
de-obfuscations of stack traces

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Commit messages:
 - 7439: Add methods in IParserExtension for Constant Pools

Changes: https://git.openjdk.java.net/jmc/pull/333/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=333&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7439
  Stats: 326 lines in 7 files changed: 311 ins; 0 del; 15 mod
  Patch: https://git.openjdk.java.net/jmc/pull/333.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/333/head:pull/333

PR: https://git.openjdk.java.net/jmc/pull/333