[XNNPACK] There is no obvious improvement when xnnpack turns on multithreading

[profiling.zip](https://github.com/microsoft/onnxruntime/files/10138007/profiling.zip)
### Describe the issue

There is no obvious improvement when xnnpack turns on multithreading.
Under the same number of threads, xnnpack will not be better than wasm.

I'm not sure if this has something to do with
kOrtSessionOptionsConfigAllowIntraOpSpinning
and
intra_op_num_threads

### To reproduce

executionProviders: ['xnnpack'],
ort.env.wasm.numThreads = 4;

### Urgency

_No response_

### ONNX Runtime Installation

Built from Source

### ONNX Runtime Version or Commit ID

master

### Execution Provider

Other / Unknown

Start with profiling.zip and reproduce the reported configuration using executionProviders: ['xnnpack'] and ort.env.wasm.numThreads = 4. Inspect how kOrtSessionOptionsConfigAllowIntraOpSpinning and intra_op_num_threads affect the comparison, then establish a measurable XNNPACK-versus-WASM result and identify the cause of the missing improvement.

Written by the indexing model from the issue text.