Phase out some old labels

I ran experiment with jenkins-debian-glue, browser tests and hhvm on
dedicated instances.  Thus I needed a specific label to tie the jobs to.

All the experiments have been integrated back in the generic puppet
class that maintains our CI slaves in labs so we can drop the now
obsoletes labels.

* Replace hasJenkinsDebianGlue by contintLabsSlave

The package jenkins-debian-glue is now in apt.wikimedia.org and
installed by puppet on all CI slaves.  So there is no point in keeping
that label around.

Updates all debian glue jobs.

* Replace hasBrowserTests by contintLabsSlave

VirtualHost and related package dependencies are installed via puppet.
The dedicated instance got dropped a while back.

Updates:
    mwext-browsertests-CirrusSearch-phantomjs
    mwext-browsertests-Flow-firefox
    mwext-browsertests-Flow-phantomjs
    mwext-browsertests-MobileFrontend-firefox
    mwext-browsertests-MobileFrontend-phantomjs
    mwext-browsertests-Translatewiki-firefox
    mwext-browsertests-Translatewiki-phantomjs
    mwext-browsertests-UniversalLanguageSelector-firefox
    mwext-browsertests-UniversalLanguageSelector-phantomjs
    mwext-browsertests-VisualEditor-firefox
    mwext-browsertests-VisualEditor-phantomjs
    qa-browsertests-build
    qa-browsertests-postmerge
    qa-browsertests-run

* Replace 'hasHhvm && hasPhpUnit' by contintLabsSlave

HHVM is installed on CI labs slaves (and not in prod) via Puppet:

    $ git grep hhvm modules/contint/
    modules/contint/manifests/packages/labs.pp:    include ::hhvm
    $

And they definitely have phpunit (via puppet).

Updates:
    mediawiki-core-regression-hhvm-REL1_19
    mediawiki-core-regression-hhvm-REL1_20
    mediawiki-core-regression-hhvm-REL1_21
    mediawiki-core-regression-hhvm-REL1_22
    mediawiki-core-regression-hhvm-REL1_23
    mediawiki-core-regression-hhvm-master

Change-Id: I2824cfb322ee296bef1ed5ed92f67d02e8aa1fac