As I mention in comment, you need to combine two reports in a single div with css of page-break something like,
$i = 0;
while($row = mysqli_fetch_assoc($result)){
if($i % 2 == 0){
echo "<div style='page-break-after:always'>";
}
/**the reports goes here**/
if($i % 2 != 0){
echo "</div>"; // Close div taking two reports in it.
}
$i++;
}