Add SDPA backend tests and refactor generate.py #2535

Job	Run time
test-readme-cpu / linux-job	11m 41s
test-evaluation-any / linux-job	17m 33s
test-advanced-any / linux-job	17m 41s
test-advanced-cpu / linux-job	17m 43s
test-evaluation-cpu / linux-job	17m 47s
test-gguf-cpu / linux-job	17m 41s
test-gguf-any / linux-job	17m 37s
test-multimodal-any / linux-job	4m 16s
test-multimodal-cpu / linux-job	4m 16s
test-native-any / linux-job	7m 11s
test-native-cpu / linux-job	6m 57s
test-quantization-any / linux-job	17m 48s
test-readme-any / linux-job	11m 48s
test-quantization-cpu / linux-job	17m 45s
	3h 7m 44s

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