checkstyle-tester: disable launch.groovy's site during diff.groovy and do checkstyle alone

[rnveach]

When launch.groovy is done it's execution, it goes through the site directory and removes non-referenced files in the generated site that don't show up in the checkstyle xml results, and some other misc stuff.
https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/launch.groovy#L239

However, when diff.groovy is the one executing launch.groovy it doesn't use this resulting site build and actually builds it's own version instead during the call to patch-diff-report-tool. All we save from the original run of launch.groovy is the resulting XML file.
https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/diff.groovy#L223

This is what makes Issue #273 possible as pure checkstyle can generate its own XML file and we don't need maven at all. This issue assumes #273 isn't done yet. If it does get done, this issue can be closed.

We should create a new option to send to launch.groovy to disable the site build and everything related to it but only run maven-checkstyle. This will save time by not doing something that isn't even needed.

[rnveach]

Updated URLs:

https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/launch.groovy#L239

contribution/checkstyle-tester/launch.groovy

Line 239 in a7077c0

def postProcessCheckstyleReport(targetDir) {

https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/diff.groovy#L223

contribution/checkstyle-tester/diff.groovy

Line 223 in a7077c0

def patchReport = "$cfg.patchReportsDir/$projectName/checkstyle-result.xml"

[rnveach]

Comparing

contribution/checkstyle-tester/launch.groovy

Line 239 in a7077c0

def postProcessCheckstyleReport(targetDir) {

to https://github.com/checkstyle/contribution/blob/master/checkstyle-tester/diff.groovy#L650

It looks like this is done already. We don't deal with the site directory anymore and fully rely on patch-diff-report-tool to generate all our HTML needs. postProcessCheckstyleReport was copied in at 80943b7 and it never included the site directory stuff.

I feel we can close this issue as basically done.