Make a new break expression of the given do

Property definitions

nitc :: astbuilder $ ADoExpr :: make_break
	# Make a new break expression of the given do
	fun make_break: ABreakExpr
	do
		var escapemark = self.break_mark
		if escapemark == null then
			escapemark = new EscapeMark(null)
			self.break_mark = escapemark
		end
		return new ABreakExpr.make(escapemark)
	end
src/astbuilder.nit:468,2--477,4