update_mir_test_checks: Fix a typo I made while preparing for commit

I accidentally added an extra arg here, so this didn't work at all.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316062 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/update_mir_test_checks.py b/utils/update_mir_test_checks.py
index 1223bde..c453a28 100755
--- a/utils/update_mir_test_checks.py
+++ b/utils/update_mir_test_checks.py
@@ -308,7 +308,7 @@
             warn('No triple found: skipping file', test_file=test)
             return
 
-        build_function_body_dictionary(test, raw_tool_output, '',
+        build_function_body_dictionary(test, raw_tool_output,
                                        triple_in_cmd or triple_in_ir,
                                        prefixes, func_dict, verbose)