[clang] [clang][utils] Add auto mode to reduction script (PR #163282)

[Arthur Eubanks via cfe-commits]

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@@ -186,22 +237,30 @@ def skip_function(func_name):
 
         self.expected_output = result
 
-    def check_expected_output(self, args=None, filename=None):
+    def check_expected_output(self, cmd=None, args=None, filename=None):
+        if not cmd:
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aeubanks wrote:

having all these default arguments makes it very hard to reason, it would be nice to clean up the callers to explicitly pass things in 

https://github.com/llvm/llvm-project/pull/163282