Issue #12700: fix test_faulthandler for Mac OS X Lion

Read from NULL raises SIGILL, not SIGSEGV, on Mac OS X Lion.
diff --git a/Lib/test/test_faulthandler.py b/Lib/test/test_faulthandler.py
index c8a8030..331dd2e 100644
--- a/Lib/test/test_faulthandler.py
+++ b/Lib/test/test_faulthandler.py
@@ -112,7 +112,8 @@
 faulthandler._read_null()
 """.strip(),
             3,
-            '(?:Segmentation fault|Bus error)')
+            # Issue #12700: Read NULL raises SIGILL on Mac OS X Lion
+            '(?:Segmentation fault|Bus error|Illegal instruction)')
 
     def test_sigsegv(self):
         self.check_fatal_error("""
@@ -192,7 +193,7 @@
 faulthandler._read_null(True)
 """.strip(),
             3,
-            '(?:Segmentation fault|Bus error)')
+            '(?:Segmentation fault|Bus error|Illegal instruction)')
 
     def test_enable_file(self):
         with temporary_filename() as filename:
@@ -203,7 +204,7 @@
 faulthandler._read_null()
 """.strip().format(filename=repr(filename)),
                 4,
-                '(?:Segmentation fault|Bus error)',
+                '(?:Segmentation fault|Bus error|Illegal instruction)',
                 filename=filename)
 
     def test_enable_single_thread(self):
@@ -213,7 +214,7 @@
 faulthandler._read_null()
 """.strip(),
             3,
-            '(?:Segmentation fault|Bus error)',
+            '(?:Segmentation fault|Bus error|Illegal instruction)',
             all_threads=False)
 
     def test_disable(self):