remove unit tests for some mw extensions

The testextensions job will fail whenever the extension is missing
PHPUnit tests. This patch:

Remove triggers for:
- mwext-Cite-testextensions-master
- mwext-wikihiero-testextensions-master
- mwext-Poem-testextensions-master

Disable voting for:
- mwext-ContributionTracking-testextensions-master

Change-Id: I40957a5d563e99616efe665953858b44004c5d76