* fixed issue with exceeded register pressure at bb end

* fixed issue with exceeded register pressure at bb end
* args of remats at block end have to live until the end of the block (live_out)
* a remat a bb end may only use a value if it is reloaded or it already arrives in
  register. It may not be the result of a different remat in this prolog (we cannot assure a proper order)
* deleting unsued PhiMs