add Intel ISA doc as load test, and make harness resilient to bad PDF loads

test/pdfs/intelisa.pdf.link

@@ -0,0 +1 @@
+http://www.intel.com/Assets/PDF/manual/253665.pdf

test/test_manifest.json

@@ -14,6 +14,12 @@
        "rounds": 1,
        "type": "load"
     },
+    {  "id": "intelisa-load",
+       "file": "pdfs/intelisa.pdf",
+       "link": true,
+       "rounds": 1,
+       "type": "load"
+    },
     {  "id": "pdfspec-load",
        "file": "pdfs/pdf.pdf",
        "link": true,

test/test_slave.html

@@ -63,7 +63,14 @@ function nextTask() {
     if (r.readyState == 4) {
       var data = r.mozResponseArrayBuffer || r.mozResponse ||
                  r.responseArrayBuffer || r.response;
-      pdfDoc = new PDFDoc(new Stream(data));
+
+      try {
+        pdfDoc = new PDFDoc(new Stream(data));
+      } catch(e) {
+        pdfDoc.numPages = 1;
+        failure = 'load PDF doc: '+ e.toString();
+      }
+
       currentTask.pageNum = 1, nextPage();
     }    
   };