Processing UT changes to get possible property values

[Luolc]

We could process the change of UT, find the changed method, and collect the property value from the config attribute.

Example PRs:
checkstyle/checkstyle#4905
checkstyle/checkstyle#4902
checkstyle/checkstyle#4853
checkstyle/checkstyle#4770
checkstyle/checkstyle#4736

We can assume the tests will be in a specific location as it should just be a change of main to test and appending Test to the class name.

[rnveach]

process the change of UT, find the changed method

Like I said in google groups, We can't always expect there to be test changes with production code. If it is just a fixing of code and not a logic change or such, we still need to run regression on it and all it's properties to verify nothing changed or is broken.
Also why do we need to only grab the property values of changed UTs. If their values didn't change in regression, then it will agree with no changes in the UTs. If they show differences, than that is unexpected since they didn't make changes to those UTs and they should add them in their PR then. We should grab all values from UTs, and not just ones that changed.

I feel we will get better results if we grab all possible values in the Test and not just the ones that changed.
The only properties that probably may not produce any results will be regular expressions for file/folder paths.

[Luolc]

Also why do we need to only grab the property values of changed UTs

I am OK with this. Whatever only changed UTs or all UTs, we would implement the same function that grab the property info. And I think grabbing from all UTs is good.