Disable failing wangle test

Summary:
Under moderate load, this part of the test would fail. When
there is resource contention, it is quite possible that the timeout will
be exceeded. A further reduction of the time spread will render this
test next to useless.

Moderate load can be as little as running all of folly's tests at once,
which is something that our testing infrastructure does quite
frequently.

fbconfig -r folly
fbmake runtests

Test Plan:
fbconfig -r folly && fbmake runtests

Reviewed By: hannesr@fb.com

Subscribers: sdwilsh, fugalh, njormrod

FB internal diff: D1576570

Tasks: 5225808

folly/wangle/test/FutureTest.cpp

@@ -727,16 +727,6 @@ TEST(Future, waitWithSemaphoreForTime) {
   p2.setValue(true);
   EXPECT_TRUE(t.isReady());
  }
- {
-  Promise<int> p;
-  Future<int> f = p.getFuture();
-  auto begin = std::chrono::system_clock::now();
-  auto t = waitWithSemaphore(std::move(f),
-    std::chrono::milliseconds(1));
-  auto end = std::chrono::system_clock::now();
-  EXPECT_TRUE( end - begin < std::chrono::milliseconds(5));
-  EXPECT_FALSE(t.isReady());
- }
  {
   auto t = waitWithSemaphore(makeFuture(),
     std::chrono::milliseconds(1));