Initialize variable for all codepaths in dynamo benchmarks (pytorch#1…

…16260)

Sometimes, the first statement that sets this variable in the try block fails due to out of memory issues and the finally block tries to delete this variable, but it was not written to in the first place.

Pull Request resolved: pytorch#116260
Approved by: https://github.com/lezcano

benchmarks/dynamo/common.py

@@ -2311,6 +2311,7 @@ def record_status(accuracy_status, dynamo_start_stats):
             # Collect the fp64 reference outputs to be used later for accuracy checking.
             fp64_outputs = None
             model_fp64 = None
+            inputs_fp64 = None
             try:
                 model_fp64, inputs_fp64 = cast_to_fp64(
                     self.deepcopy_and_maybe_ddp(model),