Managed Function calls pick IDisposable#Dispose a lot

[SamboyCoding]

Most noticeable with IEnumerator instances being created - instead of a call to the constructor being emitted, it's often replaced with a call to IDisposable.Dispose, because IEnumerator implements IDisposable.

When there are multiple methods sharing an empty body, we have to use context clues. For example in this case, it's just after a newobj instruction, so it's obviously going to be a constructor call.