Added expectedFlakey test decorator

SUMMARY
Flakey tests get two chances to pass

Also, switched a bunch of tests to use new decorator.

TEST PLAN
Add one of these decorators to a test
Edit a test to pass on the first invocation, confirm test appears as pass
Edit a test to pass on the first invocation, pass on the second, confirm test appears as xfail
Edit a test to fail on two consecutive runs, confirm test appears in results as fail/error

Differential Revision: http://reviews.llvm.org/D10721

llvm-svn: 240789
diff --git a/lldb/test/python_api/signals/TestSignalsAPI.py b/lldb/test/python_api/signals/TestSignalsAPI.py
index 804daef..8d05d37 100644
--- a/lldb/test/python_api/signals/TestSignalsAPI.py
+++ b/lldb/test/python_api/signals/TestSignalsAPI.py
@@ -12,7 +12,7 @@
     mydir = TestBase.compute_mydir(__file__)
 
     @python_api_test
-    @expectedFailureLinux # this test fails 1/100 dosep runs
+    @expectedFlakeyLinux # this test fails 1/100 dosep runs
     def test_ignore_signal(self):
         """Test Python SBUnixSignals.Suppress/Stop/Notify() API."""
         self.buildDefault()