RFR: 8343832: Enhance test summary with number of skipped tests [v3]

[Ivan Bereziuk]

> The output for Jtreg v7.5 was [enhanced](https://github.com/openjdk/jtreg/pull/217/files#diff-b6ab77bf651f1fd9a83c3ca0aab9cd24ae5c08cef41e6e257f7eaccc07c7c366R947) with [information about skipped tests](https://github.com/openjdk/jtreg/blob/master/src/share/doc/javatest/regtest/faq.md#what-do-all-those-numbers-in-the-test-results-line-mean).
> 
> Use the additional information in the "summary" block printed at the end of `make test` target.

Ivan Bereziuk has updated the pull request incrementally with one additional commit since the last revision:

  indented the comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22245/files
  - new: https://git.openjdk.org/jdk/pull/22245/files/71cc3a93..a2003355

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22245&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22245&range=01-02

  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/22245.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22245/head:pull/22245

PR: https://git.openjdk.org/jdk/pull/22245