Make a new or with two expr

Property definitions

nitc $ ASTBuilder :: make_or
	# Make a new or with two expr
	fun make_or(right_expr: AExpr, left_expr: AExpr): AOrExpr
	do
		return new AOrExpr.make(right_expr,left_expr)
	end
src/astbuilder.nit:133,2--137,4