onnxruntime

Fixed some warnings that were treated as errors when compiling with D… (#15157)

…ML in Win32/MSVC.

### Description
Use onnxruntime::narrow to silence some warnings that are turned into
errors when compiling the DML provider in Win32.

Also one case of warning turned to error for mixing int loop variable
type with a vector size() as upper bound.


### Motivation and Context
Solves
[https://github.com/microsoft/onnxruntime/issues/14595](https://github.com/microsoft/onnxruntime/issues/14595)

Co-authored-by: bengt.gustafsson <bengt.gustafsson@contextvision.se>