Enable flaky test that was fixed some time ago.

Review URL: http://codereview.chromium.org/80001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1760 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/cctest.status

@@ -27,9 +27,6 @@
 
 prefix cctest
 
-# BUG(96): Fix this flaky test.
-test-debug/ThreadedDebugging: PASS || FAIL
-
 # BUG(281): This test fails on some Linuxes.
 test-debug/DebuggerAgent: PASS, (PASS || FAIL) if $system == linux