Improve parallelization of CSP and XSSAuditor reporting tests.

LayoutTests/http/tests/security/contentSecurityPolicy/resources/save-report.php

 <?php
 function undoMagicQuotes($value) {
     if (get_magic_quotes_gpc())
         return stripslashes($value);
     return $value;
 }
 
-$reportFile = fopen("csp-report.txt.tmp", 'w');
+$reportFile = fopen("csp-report." . $_GET["test"] . ".tmp", 'w');
 $httpHeaders = $_SERVER;
 ksort($httpHeaders, SORT_STRING);
 foreach ($httpHeaders as $name => $value) {
     if ($name === "CONTENT_TYPE" || $name === "HTTP_REFERER" || $name === "REQUEST_METHOD") {
         $value = undoMagicQuotes($value);
         fwrite($reportFile, "$name: $value\n");
     }
     if ($name === "HTTP_COOKIE" && $_COOKIE["cspViolationReportCookie"]) {
         fwrite($reportFile, "Cookie: cspViolationReportCookie=" . $_COOKIE["cspViolationReportCookie"] . "\n");
     }
 }
 
 foreach ($_COOKIE as $name => $value)
     setcookie($name, "deleted", time() - 60, "/");
 
 fwrite($reportFile, "=== POST DATA ===\n");
 fwrite($reportFile, file_get_contents("php://input"));
 fclose($reportFile);
-rename("csp-report.txt.tmp", "csp-report.txt");
+rename("csp-report." . $_GET["test"] . ".tmp", "csp-report." . $_GET["test"] . ".txt");
 ?>