[MLIR][python bindings] Add more basic AttrBuilder for _ops_gen.py files

Add more attribute builders, such as "F32Attr", "F64Attr" and "F64ArrayAttr", which are useful to create operations by python bindings. For example, tosa.clamp in _tosa_ops_gen.py need 'F32Attr'.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D150757