Qwen2/3 MoE + GGUF model support (restored) (#42854)
This commit restores Qwen2/3 MoE + GGUF support in Transformers v5.
In this version, handling of MoE tensors are significantly changed so
that support for all MoE + GGUF models ... (okay, only) Qwen2/3 MoE
models in Transformers v4 is now broken.
This commit now adopts new tensor handling, along with extended
`TensorProcessor` with capabilities to handle not only tensor data
but also tensor mappings. In this process, Qwen2/3 MoE-specific hack
is moved to `Qwen2MoeTensorProcessor`, making the main function to look
more model-agnostic.
This is fully tested on Qwen2 MoE `Qwen1.5-MoE-A2.7B` and partially on
Qwen3 MoE `Qwen3-30B-A3B-Thinking-2507` (due to memory constraints).
Signed-off-by: Tsukasa OI <floss_llm@irq.a4lg.com>
