Set SE_START_XVFB: 'true' for selenium w3c testing
Problem/Motivation
Per #3494332: Functional Javascript tests are silently skipped on Gitlab CI due to selenium standalone configuration - core's javascript tests were being skipped when selenium ran out of sessions, because it was not properly shutting down sessions when a test method finished. Because skipping is silent, the job just passes.
This is likely to affect any contributed module with more than a handful of functional js tests. Once the core issue lands, instead of silently skipping, those pipelines will fail when selenium can't open a connection.
I think just changing that one line might be enough, but it might also be good to review the timeout and max session variables too in light of this.
Steps to reproduce
Proposed resolution
Remaining tasks
User interface changes
API changes
Data model changes
Related issue: Issue #3494332
Edited by drupalbot