Don't emit redundant creation methods

[madsmtm]

Methods such as MTLAccelerationStructurePassDescriptor::accelerationStructurePassDescriptor() are redundant and less efficient than the alternative MTLAccelerationStructurePassDescriptor::new(). We should avoid emitting them (Swift seems to do this too).

This probably requires a better understanding of method names (e.g. we have to figure out that "MTLAccelerationStructurePassDescriptor" is equal to "accelerationStructurePassDescriptor" except for the prefix).