When getting default project from session, get it only if the script info is not orphan

Since the closed script info's that are orphan arent removed immediately but on next open request, treat the orphan script infos as if they are not present in the session

src/server/scriptInfo.ts

@@ -328,6 +328,10 @@ namespace ts.server {
             }
         }
 
+        isOrphan() {
+            return this.containingProjects.length === 0;
+        }
+
         /**
          *  @param line 1 based index
          */