devserver: Revise integration tests server startup logic.

* We shift to having the devserver bind to an arbitrary port by default
  for test purposes. This is more robust and saves us from relying on
  heuristic, iterative attempts.

* Revise the test classes hierarchy to distinguish "auto-started server"
  tests from others; this will be needed for specifically testing the
  devserver's port binding behavior.

* Small refactoring for better code reusability, clarity.

TEST=Integration tests pass.

Change-Id: Ia17b580c393ecc641dccc8e88608e9807d0eea87
Reviewed-by: Gilad Arnold <>
Commit-Queue: Gilad Arnold <>
Tested-by: Gilad Arnold <>
1 file changed