fix: meta-reference parallel utils bug, use isinstance not equality #1

Job	Run time
generate-matrix	5s
build-single-provider	17s
build-custom-container-distribution	1m 13s
build (bedrock, container)	1m 3s
build (cerebras, container)	1m 11s
build (cerebras, venv)	24s
build (bedrock, venv)	21s
build (experimental-post-training, container)	1m 35s
build (dell, venv)	24s
build (experimental-post-training, venv)	50s
build (fireworks, venv)	24s
build (dell, container)	1m 17s
build (dev, container)	1m 9s
build (fireworks, container)	1m 20s
build (dev, venv)	32s
build (groq, venv)	19s
build (hf-endpoint, venv)	22s
build (ci-tests, venv)	24s
build (hf-serverless, container)	1m 18s
build (hf-serverless, venv)	30s
build (groq, container)	1m 10s
build (ci-tests, container)	1m 8s
build (nvidia, venv)	19s
build (hf-endpoint, container)	1m 5s
build (ollama, venv)	20s
build (meta-reference-gpu, container)	1m 43s
build (meta-reference-gpu, venv)	46s
build (remote-vllm, venv)	30s
build (passthrough, venv)	29s
build (nvidia, container)	1m 4s
build (ollama, container)	1m 4s
build (remote-vllm, container)	1m 5s
build (open-benchmark, venv)	19s
build (tgi, venv)	25s
build (passthrough, container)	1m 15s
build (sambanova, container)	1m 3s
build (sambanova, venv)	24s
build (open-benchmark, container)	58s
build (vllm-gpu, container)	1m 56s
build (together, venv)	26s
build (vllm-gpu, venv)	49s
build (tgi, container)	1m 6s
build (verification, container)	1m 15s
build (verification, venv)	24s
build (together, container)	1m 14s
	37m 15s

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