Fix calculated build time in custom data by using System.currentTimeM…

[valtaroth]

The calculated build time for custom data is terribly wrong for pipeline builds where the build is still running and the duration cannot be fetched from Jenkins itself. The timestamp provided to CustomDataPointGenerator used for the calculation is in nanoseconds while it is required to be in milliseconds. Since JenkinsBasePointGenerator is calculating the timestamp using System.currentTimeMillis(), I added that calculation here too. Alternatively, if the provided timestamp is supposed to be used although it isn't in the base point generation, the start time needs to be converted to nanoseconds before calculating the duration and the result converted back to milliseconds.

[asimell]

The reason why it uses the timestamp is, because there is an option to use build scheduled time as the timestamp instead of the time the point is generated. So, the solution should be to convert to nanoseconds and then back to milliseconds.

[asimell]

Actually, the timestamp / 1000000 is what is supposed to be in startTime and currTime should be System.currentTimeMillis(). Otherwise, having the start time as job scheduled time will result in the build_time to always be 0 (build.getTimeInMillis() - build.getTimeInMillis())

[valtaroth]

Sorry, I totally misunderstood you then. I flipped it now, should hopefully be fine.