Issue #16714: use 'raise' exceptions, don't 'throw'.

Patch by Serhiy Storchaka.
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 4ad7350..f4e8aba 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -824,7 +824,7 @@
             posix.rename(support.TESTFN + 'ren', support.TESTFN)
             raise
         else:
-            posix.stat(support.TESTFN) # should not throw exception
+            posix.stat(support.TESTFN) # should not raise exception
         finally:
             posix.close(f)
 
@@ -842,7 +842,7 @@
     def test_unlink_dir_fd(self):
         f = posix.open(posix.getcwd(), posix.O_RDONLY)
         support.create_empty_file(support.TESTFN + 'del')
-        posix.stat(support.TESTFN + 'del') # should not throw exception
+        posix.stat(support.TESTFN + 'del') # should not raise exception
         try:
             posix.unlink(support.TESTFN + 'del', dir_fd=f)
         except: