[JIT] Optimize FunctionSchema::checkArg for the Tensor case. (#48034)

Summary:
Pull Request resolved: #48034

The Tensor case is one of the most common and the existing check can be
made faster. This results in a ~21% improvement on DeepAndWide model and
would improve other models as well.

Before the change:
```
505[ms]
491[ms]
514[ms]
538[ms]
514[ms]
554[ms]
556[ms]
512[ms]
516[ms]
527[ms]
```

After the change:
```
406[ms]
394[ms]
414[ms]
423[ms]
449[ms]
397[ms]
410[ms]
389[ms]
395[ms]
414[ms]
```

Differential Revision: D24999486

Test Plan: Imported from OSS

Reviewed By: zdevito

Pulled By: ZolotukhinM

fbshipit-source-id: 7139a3a38f9c44e8ea793afe2fc662ff51cc0460

aten/src/ATen/core/function_schema_inl.h

@@ -151,6 +151,10 @@ inline void FunctionSchema::checkArg(
     const IValue& value,
     const Argument& argument,
     optional<size_t> pos) const {
+  if (value.isTensor() && argument.type() == TensorType::get()) {
+    // Fast-path for the common case
+    return;
+  }
   if (!value.type()->isSubtypeOf(argument.type())) {
     TORCH_CHECK(
         false,