Add FP8 placeholder support to ExecuTorch serialization#19043

YufengShi-dudu wants to merge 4 commits intopytorch:mainpytorch/executorch:mainfrom

YufengShi-dudu:add-fp8-placeholder-support-for-serializationYufengShi-dudu/executorch:add-fp8-placeholder-support-for-serializationCopy head branch name to clipboard