Ignore an additional thread in test 911

This was causing failures in cts

Bug: 37579245
Test: ./test/testrunner/testrunner.py --host -j40
Test: cts-tradefed run cts-dev --module CtsJvmtiRunTest911HostTestCases
Change-Id: Iee5c1874de225b98016994e046378268fb68e2fb
(cherry picked from commit 3cf6a70e)
Merged-In: Iaeba26b9554dee5cba6ef04e91d4a2664c7e94d0