Revert "[ISSUE JENKINS-25280] temporary workaround bug in core so that test failures are expanded correctly."

This reverts commit badbfec68c356945772d04b39cf2251a864300ef.

Change-Id: Ide6d5b3fe8a49aa48efbb1813dbb1e9d4b9e2a02
[FIXED JENKINS-25280] update to latest LTS and junit plugin to pick up fix

Change-Id: Idb168fa58572e4591a9cf5d478464ea20ebc35b1