oeqa/sstatetests: Fix race issue

Under some load conditions, the result event can come back before the
command complete event. If that happens, the code would hang
indefinitely.

Rework the code to wait for both events and avoid the hang.

(From OE-Core rev: 8cfc94a4404c54bc73eab9f98d9da1f84c2135ad)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/sstatetests.py

@@ -772,15 +772,16 @@ addtask tmptask2 before do_tmptask1
 
             def find_siginfo(pn, taskname, sigs=None):
                 result = None
+                command_complete = False
                 tinfoil.set_event_mask(["bb.event.FindSigInfoResult",
                                 "bb.command.CommandCompleted"])
                 ret = tinfoil.run_command("findSigInfo", pn, taskname, sigs)
                 if ret:
-                    while True:
+                    while result is None or not command_complete:
                         event = tinfoil.wait_event(1)
                         if event:
                             if isinstance(event, bb.command.CommandCompleted):
-                                break
+                                command_complete = True
                             elif isinstance(event, bb.event.FindSigInfoResult):
                                 result = event.result
                 return result