Save ping+beacon test status in temporary directory.

LayoutTests/http/tests/navigation/resources/check-beacon.php

 <?php
-$beaconFilename = "beacon" . (isset($_REQUEST['name']) ? $_REQUEST['name'] : "") . ".txt";
-$retries = isset($_REQUEST['retries']) ? (int)$_REQUEST['retries'] : -1;
+require_once '../../resources/portabilityLayer.php';
+
+$beaconFilename = sys_get_temp_dir() . "/beacon" . (isset($_REQUEST['name']) ? $_REQUEST['name'] : "") . ".txt";
+
+$max_attempts = 700;
+$retries = isset($_REQUEST['retries']) ? (int)$_REQUEST['retries'] : $max_attempts;
 while (!file_exists($beaconFilename) && $retries != 0) {
     usleep(10000);
     # file_exists() caches results, we want to invalidate the cache.
     clearstatcache();
     $retries--;
 }
 
 header('Content-Type: text/plain');
 header('Access-Control-Allow-Origin: *');
 if (file_exists($beaconFilename)) {
-    echo "Beacon sent successfully\n";
-    $beaconFile = fopen($beaconFilename, 'r');
-    while ($line = fgets($beaconFile)) {
-        $trimmed = trim($line);
-        if ($trimmed != "")
-            echo "$trimmed\n";
+    $beaconFile = false;
+    if (is_readable($beaconFilename)) {
+        $beaconFile = fopen($beaconFilename, 'r');
     }
-    fclose($beaconFile);
-    unlink($beaconFilename);
+    if ($beaconFile) {
+        echo "Beacon sent successfully\n";
+        while ($line = fgets($beaconFile)) {
+            $trimmed = trim($line);
+            if ($trimmed != "")
+                echo "$trimmed\n";
+        }
+        fclose($beaconFile);
+        unlink($beaconFilename);
+    } else {
+        echo "Beacon status not readable\n";
+    }
 } else {
     echo "Beacon not sent\n";
 }
 ?>