RFR: Move testing information from the PR body to checks [v2]

[Robin Westberg]

> When summarizing pre-submit test results for a PR, show the results as a number of checks instead of a table in the PR body. This makes them more similar to the source information, and avoids excessive PR body updates.

Robin Westberg has updated the pull request incrementally with one additional commit since the last revision:

  Only create summarized checks and put the individual job details in the check summary

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Changes:
  - all: https://git.openjdk.java.net/skara/pull/962/files
  - new: https://git.openjdk.java.net/skara/pull/962/files/c1133a05..39cf8c41

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=962&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=962&range=00-01

  Stats: 145 lines in 3 files changed: 77 ins; 15 del; 53 mod
  Patch: https://git.openjdk.java.net/skara/pull/962.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/962/head:pull/962

PR: https://git.openjdk.java.net/skara/pull/962