Backport the functionality to permit propagation of NULL to the database for parameters in stored procedure invocations. Setting hibernate.proc.param_null_passing="true" will globally enable passing null as the stored procedure parameter value when no value is provided. Default will be "false".

NOTE: HHH-9548 allows the global value to be overridden on a per parameter basis; this functionality cannot be backported to 5.0 due to SPI changes.