[cherry-picked from AOSP and slightly refactored by yole]

Change StatisticsService extension point.

Change the StatisticsService extension point to a bean/keyed EP
which key is set by the <statistics> element from AppInfo.xml

StatisticsService EP can now override the text used
in the statistics notification/configuration.
Do enforce line feed between a field and instance block initializer in a situation when formatter is not called explicitly
implement fix workaround: if abstract method is package local and package is not the same - suggest to make method protected/public instead (IDEA-61220)
[^vassily] better icon for detached frame on XWindow