RFR: 5700: Improve file and socket IO rule result texts [v4]

[Jean-Philippe Bempel]

> Add new information along with longest event:
>  - report the total and average pauses for the entire recording.
>  - report the sum of all IO events for that file or host of the longest event
> Add also some mock classes for IItemCollection with some mock events

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

  fix typos

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Changes:
  - all: https://git.openjdk.java.net/jmc/pull/138/files
  - new: https://git.openjdk.java.net/jmc/pull/138/files/2b2c7ef6..409e3407

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jmc&pr=138&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jmc&pr=138&range=02-03

  Stats: 7 lines in 4 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/jmc/pull/138.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/138/head:pull/138

PR: https://git.openjdk.java.net/jmc/pull/138