Fix type promotion of float8_e5m2 and float8_e4m3fn (#110279)
There is an issue with float8 type promotion, because _promoteTypesLookup doesn't contain records for few types between bfloat16 and float8.
I have simply moved float8 types just after bfloat16, however I'm not sure if it doesn't break serialization.
Please, decide if it can stay like this, or should I insert missing records filled with "ud" into _promoteTypesLookup instead of moving types.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/110279
Approved by: https://github.com/albanD
