Report pipeline name in build status message

Slightly enhance the success and failures messages reported by the
pipelines.

* Naming the pipeline makes it easier to distinguish between the
  build success of the "test" pipeline (following patch submission
  or rebase), and the build of the "gate-and-submit" pipeline
  (following CR+2). Especially when they happen close to each other
  and are racing this can be confusing.

  We already did this for Post-merge, doing it for Basic test,
  Main test and Gate pipeline as well.

Bug: 50327
Change-Id: Ib9170f54d0591bee6082e8b1b9136c446c620869