[Quantization] Fix static quantize runner usage.

[minfhong-qti]

Description

• 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

Fix two issues in static_quantize_runner usage.