Mark pkg/stack_trace/test/chain_test as timing out on browsers.

BUG=dartbug.com/18142
R=ricow@google.com

Review URL: https://codereview.chromium.org//232713002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@34916 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/pkg/pkg.status b/pkg/pkg.status
index b38d22e..b0bd22e 100644
--- a/pkg/pkg.status
+++ b/pkg/pkg.status
@@ -191,7 +191,7 @@
 
 [ $compiler == dart2js && $browser ]
 stack_trace/test/vm_test: Fail, OK # VM-specific traces
-stack_trace/test/chain_test: Fail # Issues 15171 and 15105
+stack_trace/test/chain_test: Fail, Timeout # Issues 15171, 15105, and 18142
 crypto/test/sha256_test: Slow, Pass
 crypto/test/sha1_test: Slow, Pass
 polymer/example/component: Fail # Issue 13198