Operator unit tests broken

[winston-zillow]

Many unit tests seem to be broken for me on the develop branch.

In particular, the hard-coding of output var type is problematic:

    def append_input_output(self, block, op_proto, np_list, persistable_list, is_input):
        ...
        def create_var(block, name, np_list, var_proto):
            ...
            return block.create_var(
                dtype='float32',
                shape=shape,
                persistable=persistable,
                lod_level=lod_level,
                name=name)

However, making the type from np_val will fix some tests but break many others.