Pragma never noinit

In function resolution we warned users about using noinit with certain types because it did not work at the moment.  This was done by checking that the type in question was one of the known failure types.  However, if a developer were to create a type they did not think should work with noinit, they would have to alter the compiler to recognize and warn about this case.  The impact was partially theoretical in Chapel as it stands today - a user on their own could just remember not to use noinit with the type, and if code containing that type was submitted back, perhaps a comment would be needed so that anyone hoping to use that type would not make that mistake.

However, it is hoped that we can move to a world where return temps are not default initialized unless necessary, since these variables will be assigned to before they are returned.  In this case, types that may not otherwise have seen noinit would have it applied to them when a variable of that type was returned.  In such cases, it would be essential for the developer to inform the compiler that this type must never use noinit, so that noinit was not inserted for the return temp of that type.  Thus, the solution at the moment is to create a pragma "do not init", which would allow a user or developer to specify this case without needed to alter the compiler.