onnxruntime

Update model_tests.cc: avoid auto adding new tests from new opsets (#17084)

### Description
1. Update model_tests.cc: avoid auto adding new tests from new opsets. 
2. Simplify the "ConcatPathComponent" function. It does not need to be a
template.

### Motivation and Context
All our Windows/Linux CI build machines are preloaded with some test
data. In model_tests.cc, we auto add all of them to
onnxruntime_test_all.exe's unit tests. However, it causes problems when
we update the CI build machine images: new data could cause pipelines
suddenly failing.
Therefore, instead of auto discovering test data and adding all of them
to tests, this PR changes it to explicitly specify the opset names.

This change doesn't impact how Web CI pipeline runs its tests.

Going forward, the workflow would be like:
Step 1: update the onnx version in deps.txt
Step 2: Update js/scripts/prepare-onnx-node-tests.ts. Like #16943 .
Better to put step 1 and step 2 in the same PR.
Step 3: onnxruntime-es team regenerates VM images, test them and deploy
them.
Step 4: Enable the new opset test data for EPs. 


[AB#18340](https://aiinfra.visualstudio.com/6a833879-cd9b-44a4-a9de-adc2d818f13c/_workitems/edit/18340)