onnxruntime

Add automatic generation of tensors for Onnxruntime Perf Runner (#3448)

* Add flag to enable automatic generation of input for models with tensor inputs

* change wording of variable

* Naming convention changes to variables

* Handle free dimensions

* Comment with default allocator

* variable rename

* Remove input_count

* Cast to size_t to avoid warning

Co-authored-by: Ryan Lai <ryalai96@gamil.com>