swift234

[verifier] Make sure all SILFunctions only have one out parameter and that out parameter is the first argument to the function.

This is already an assumption in SILFunctionType:

  bool hasIndirectResult() const {
    return !getParameters().empty()
      && getParameters()[0].isIndirectResult();
  }
  SILParameterInfo getIndirectResult() const {
    assert(hasIndirectResult());
    return getParameters()[0];
  }

This just bakes the invariant into the IR so it is clear when writing tests that
this is not an issue.

I also updated function_ref and partial_apply to have the same such checks. This
should handle the majority of the cases.

Swift SVN r22119