8029627: Allow duplicate bugid for changeset in jdk8 update forest

Reviewed-by: robilad
diff --git a/nashorn/.jcheck/conf b/nashorn/.jcheck/conf
index 6d0dbe4..5bd24b1 100644
--- a/nashorn/.jcheck/conf
+++ b/nashorn/.jcheck/conf
@@ -1 +1,2 @@
 project=jdk8
+bugids=dup