Add Big models pipeline (#19222)
### Description
2 models are added in CI.
Stabe diffusion Model stage is based on
https://github.com/microsoft/onnxruntime/blob/main/onnxruntime/python/tools/transformers/models/stable_diffusion/README.md
LLama2 FP16 is based on https://github.com/microsoft/Llama-2-Onnx.
12G GPU memory is not enough, so I choose T4 to run it.
### Motivation and Context
Add regular E2E test for big models.
It will be triggered in main build, that is, it'll run after one PR is
merged.
More models will be added later.
### Test Runs ###
https://dev.azure.com/onnxruntime/onnxruntime/_build/results?buildId=1275191&view=results
