Add bugids=dup to .jcheck/conf files for JDK 10

diff -r 2b621c408db2 .jcheck/conf
--- a/.jcheck/conf Tue Jun 27 08:43:15 2017 -0700
+++ b/.jcheck/conf Wed Jun 28 09:36:32 2017 -0700
@@ -1,1 +1,2 @@
 project=jdk10
+bugids=dup