onnxruntime

94e7a1c6 - Initial change to enable WebGPU EP to suport plugin API (#25705)

Initial change to enable WebGPU EP to suport plugin API (#25705) ### Description This is the first PR among a list of PRs to make WebGPU EP able to use the plugin API (EP ABI). This PR adds new build flags for WebGPU: - `--use_webgpu shared_lib` to enable building WebGPU EP based on the plugin API (EP ABI). - keep `--use_webgpu` or `--use_webgpu static_lib` behavior no change. Currently `--use_webgpu shared_lib` will fail, but it is fine because no one is using it. #### Why making small changes Huge PR is very difficult to review. Splitting a huge PR into multiple ones has the benefits that each small PR is relatively easier to review. #### Plan - [x] STEP.1 - Introduce build flags (this PR) - [ ] STEP.2 - Changes some macros and util functions to support both static and shared - [ ] STEP.3 - Core implementation of EP API based WebGPU EP - [ ] STEP.4 - Builds/Tests/etc.