RFR: 6936: Parser should track statistics during parsing [v3]

[Jean-Philippe Bempel]

> Add new `IParserStats` interface implemented by `EventCollection`.
> That way, `IItemCollection` is not touched, but you need to cast the
> instance to `IParserStats`.
> Support of old (v0.x) JFR format.
> During parsing, we collect number of events per type, the size, number
> of chunks and version of the file.
> We also track for version 1.x/2.x the number of skipped events.
> `RecordingPrinter` tool class is modified to support a summary verbosity mode
> and `-summary` option to print statistics per event type.

Jean-Philippe Bempel has updated the pull request incrementally with one additional commit since the last revision:

  Add Oracle copyright header

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Changes:
  - all: https://git.openjdk.java.net/jmc/pull/219/files
  - new: https://git.openjdk.java.net/jmc/pull/219/files/9f966581..0ea61a16

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=219&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=219&range=01-02

  Stats: 32 lines in 1 file changed: 32 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jmc/pull/219.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/219/head:pull/219

PR: https://git.openjdk.java.net/jmc/pull/219