Changes to Kudu functional to work On-Prem

I made the following changes for our functionals to work on-premise
1) 4 test cases were randomizing site names twice. Now we pass a parameter to Run, if we have already randomized it in the test case itself. 

2) The test case changes to use (1) will be checked into private kudu. The following test cases will be changed
Kudu.FunctionalTests.AntaresWebSiteConfigTests.UpdatingAppSettingsArePropagatedForPHP 
Kudu.FunctionalTests.AntaresWebSiteConfigTests.UpdatingAppSettingsAndConnStringsArePropagatedForMVC
Kudu.FunctionalTests.AntaresWebSiteConfigTests.ExtraBuildArgumentsAreApplied
Kudu.FunctionalTests.LogStreamManagerTests.TestLogStreamAppShutdown 

3) FirstPushDeletesHostingStartHtmlFile  has been changed to work both on-prem and azure. On-prem version of hostingstart.html has no <h1> tags