[Rev 04] RFR: 6640: Run spotless and tests as part of the workflow

[Marcus Hirt]

The pull request has been updated with additional changes.

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Added commits:
 - c41f5c0f: Making the .gitignore better whilst forcing a rerun to ensure that passing on all platforms was more than a lucky break

Changes:
  - all: https://git.openjdk.java.net/jmc/pull/10/files
  - new: https://git.openjdk.java.net/jmc/pull/10/files/e2d8a1d7..c41f5c0f

Webrevs:
 - full: https://webrevs.openjdk.java.net/jmc/10/webrev.04
 - incr: https://webrevs.openjdk.java.net/jmc/10/webrev.03-04

  Issue: https://bugs.openjdk.java.net/browse/JMC-6640
  Stats: 11 lines in 1 file changed: 11 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jmc/pull/10.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/10/head:pull/10

PR: https://git.openjdk.java.net/jmc/pull/10