* Initializers lowering fix: clone init blocks.
In order to let following phases to modify IR we need to clone init blocks
for each constructor before inserting it.
* Used DeepCopyIRTreeWithDescriptors.
* Shared variables lowering must be performed before local functions lowering.
Local functions lowering makes all variables non-shared, thus they must be
transformed into Ref<> before this.
* Moved all initializers into a method.
In order not to deal with copying of IR at all it is easier to create a
method 'initialize' which will be called from each constructor.
* Used right parameters for call.
* If class has primary constructor then move initializers to it.
* review fixes
Igor Chevdar
ed2191b4a3