[lit] Support older Python 3.x versions without enum.auto()

(cherry picked from commit 6bedcf0)

Author: davezarzycki

llvm/utils/lit/lit/cl_arguments.py

@@ -9,8 +9,10 @@
 
 
 class TestOrder(enum.Enum):
-    DEFAULT = enum.auto()
-    RANDOM = enum.auto()
+    # Older Python versions don't have enum.auto().
+    # Does upstream LLVM not have a build bot with Python 3.5?
+    DEFAULT = 1
+    RANDOM = 2
 
 
 def parse_args():