8030068: Update .jcheck/conf files for JDK 9

Reviewed-by: mr
diff --git a/.jcheck/conf b/.jcheck/conf
index 6d0dbe4..5c6f62d 100644
--- a/.jcheck/conf
+++ b/.jcheck/conf
@@ -1 +1 @@
-project=jdk8
+project=jdk9