Make XFAIL on TestPrintStackTraces more specific

the thread creation failure was fixed, but a backtracing problem remains in some situations.

llvm-svn: 240635

lldb/test/python_api/lldbutil/process/TestPrintStackTraces.py

@@ -18,10 +18,7 @@ class ThreadsStackTracesTestCase(TestBase):
         # Find the line number to break inside main().
         self.line = line_number('main.cpp', '// Set break point at this line.')
 
-    # fails on Linux i386 llvm.org/pr23043
-    # fails 78/100 on Linux x86_64 when running against remote lldb-platform
-    # failed 11/200 on the linux build bot
-    @expectedFailureLinux
+    @expectedFailureAll("llvm.org/pr23043", ["linux"], "gcc", archs=["i386"]) # We are unable to produce a backtrace of the main thread when the thread is blocked in fgets
     @python_api_test
     def test_stack_traces(self):
         """Test SBprocess and SBThread APIs with printing of the stack traces."""