[Quantization] Fix static quantize runner usage. (#26624)
### Description
<!-- Describe your changes. -->
- Input pb files were read in incorrect order.
- Cause: Python `sorted` was used to acquire sorted input files in
order. However, the input files would be in incorrect order since "10"
is lexicographically smaller than "2".
- Fix: Revise to enumerating indices to read input files.
- CumSum's output wasn't quantized.
- Cause: CumSum wasn't registered into QDQ registry.
- Fix: Register CumSum with QDQDirect8bitOp.
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
Fix two issues in `static_quantize_runner` usage.
