Add tests for YamlParser and patch 2.6 minidom

Test full build job XML produced by the YamlParser object which exposed
differences in how the XML was being written on python 2.6 versus newer
versions of python.

Differences were whitespace only, but made testing and validating the
xml outputted across multiple versions of python difficult.

Code now patches the python 2.6 writexml method on the Element class in
the xml.dom.minidom module, with a version of the method taken from
python 2.7.5.

Removed the now obsolete regex that was reformatting the output on
python 2.6.

Change-Id: I26c100b6adfbcb9b197bb06cd162855adaaf24c5
Merge "Add tests for YamlParser and patch 2.6 minidom"