TSAN hits an internal assertion on a self-join, and the test is not
really that useful, so let's just remove it.

BUG=https://code.google.com/p/thread-sanitizer/issues/detail?id=88
LOG=n

Review URL: https://codereview.chromium.org/824243007

Cr-Commit-Position: refs/heads/master@{#26217}