Fix a bug in lldbutil.expect_state_changes

The logic for skipping over the stop-and-restart events was incorrect as it was also skipping the
expectations. Implement it properly. No test is affected by this as they were not encountering
these events, but I encountered this issue when trying to use this function in a new test.

llvm-svn: 256928
diff --git a/lldb/packages/Python/lldbsuite/test/lldbutil.py b/lldb/packages/Python/lldbsuite/test/lldbutil.py
index 1aacf87..339619d 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbutil.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbutil.py
@@ -737,17 +737,25 @@
 def expect_state_changes(test, listener, states, timeout = 5):
     """Listens for state changed events on the listener and makes sure they match what we
     expect. Stop-and-restart events (where GetRestartedFromEvent() returns true) are ignored."""
-    event = lldb.SBEvent()
+
     for expected_state in states:
-        if not listener.WaitForEvent(timeout, event):
-            test.fail("Timed out while waiting for a transition to state %s" %
-                lldb.SBDebugger.StateAsCString(expected_state))
+        def get_next_event():
+            event = lldb.SBEvent()
+            if not listener.WaitForEvent(timeout, event):
+                test.fail("Timed out while waiting for a transition to state %s" %
+                    lldb.SBDebugger.StateAsCString(expected_state))
+            return event
 
-        got_state = lldb.SBProcess.GetStateFromEvent(event)
-        if got_state == lldb.eStateStopped and lldb.SBProcess.GetRestartedFromEvent(event):
-            continue
+        event = get_next_event()
+        while (lldb.SBProcess.GetStateFromEvent(event) == lldb.eStateStopped and
+                lldb.SBProcess.GetRestartedFromEvent(event)):
+            # Ignore restarted event and the subsequent running event.
+            event = get_next_event()
+            test.assertEqual(lldb.SBProcess.GetStateFromEvent(event), lldb.eStateRunning,
+                    "Restarted event followed by a running event")
+            event = get_next_event()
 
-        test.assertEqual(expected_state, got_state)
+        test.assertEqual(lldb.SBProcess.GetStateFromEvent(event), expected_state)
 
 # ===================================
 # Utility functions related to Frames