Removed bogus threading test to make TSAN happy.

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}

test/unittests/base/platform/platform-unittest.cc

@@ -34,24 +34,6 @@ TEST(OS, GetCurrentProcessId) {
 }
 
 
-namespace {
-
-class SelfJoinThread FINAL : public Thread {
- public:
-  SelfJoinThread() : Thread(Options("SelfJoinThread")) {}
-  void Run() FINAL { Join(); }
-};
-
-}  // namespace
-
-
-TEST(Thread, DISABLE_ON_ANDROID(SelfJoin)) {
-  SelfJoinThread thread;
-  thread.Start();
-  thread.Join();
-}
-
-
 namespace {
 
 class ThreadLocalStorageTest : public Thread, public ::testing::Test {