Remove unused TempFileUtil
Remove unused TempFileUtil

All usages have been replaced with JUnit's TemporaryFolder, so we no
longer need to reinvent the wheel.

Change-Id: I88523c95124ea46dae3a74c2eb1a1f961dbbf5d2

qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit