[opaque pointer types] Fix the CallInfo passed to EmitCall in some edge cases.

[jyknight]

Currently, EmitCall is emitting a call instruction using a function
type derived from the pointee-type of the callee. This should be the
same as the type created from the CallInfo parameter, but in some
cases an incorrect CallInfo was being passed.

All of these fixes were discovered by the addition of the assert in
EmitCall which verifies that the passed-in CallInfo matches the
Callee's function type.

As far as I know, these issues caused no bugs at the moment (but would
potentially cause problems when removing pointee types.)

List of fixes:

• arrangeCXXConstructorCall was passing an incorrect value for the
  number of Required args, when calling an inheriting constructor
  where the inherited constructor is variadic. (The inheriting
  constructor doesn't actually get passed any of the user's args, but
  the code was calculating it as if it did).

• arrangeFreeFunctionLikeCall was not including the count of the
  pass_object_size arguments in the count of required args.

• OpenCL uses other address spaces for the "this" pointer. However,
  commonEmitCXXMemberOrOperatorCall was not annotating the address
  space on the "this" argument of the call.

• Destructor calls were being created with EmitCXXMemberOrOperatorCall
  instead of EmitCXXDestructorCall in a few places. This was a problem
  because the calling convention sometimes has destructors returning
  "this" rather than void, and the latter function knows about that,
  and sets up the types properly (through calling
  arrangeCXXStructorDeclaration), while the former does not.

• generateObjCGetterBody: the objc_getProperty function returns 'id',
  but was being called as if it returned the property type. (The
  return value gets downcast to the propererty type after the call).

• OpenMP user-defined reduction functions (#pragma omp declare
  reduction) can be called with a subclass of the declared type. In
  such case, the call was being setup as if the function had been
  actually declared to take the subtype, rather than the base type.