[quant] Move the order of x86 engine to avoid changing the default qengine (#86631)
since the default qengine is the last element of the engine in supported_engines list, adding x86 qengine in the end of the list changes the default quantized engine as well. this PR will be a short term fix to revert the changes. We have an issue here to track the proper fix: https://github.com/pytorch/pytorch/issues/86404
Motivation:
a meta internal team found that the inference failed in onednn prepacking with error: "could not create a primitive descriptor for a reorder primitive." in a COPPER_LAKE machine, we are working with intel to repro and fix the problem. in the mean time, we'll revert the changes of default option back to fbgemm
Pull Request resolved: https://github.com/pytorch/pytorch/pull/86631
Approved by: https://github.com/vkuzo
