core(driver): increase default timeout to 45s (#3741)

lighthouse-core/gather/driver.js

@@ -26,7 +26,7 @@ const _uniq = arr => Array.from(new Set(arr));
 
 class Driver {
   static get MAX_WAIT_FOR_FULLY_LOADED() {
-    return 30 * 1000;
+    return 45 * 1000;
   }
 
   /**