r205158 - RTTI: refactor the uniqueness question into CGCXXABI.

[Rafael Espíndola]

>    // If we're supposed to demote the visibility, be sure to set a flag
>    // to use a string comparison for type_info comparisons.
> -  UniqueRTTIKind uniqueRTTI = classifyUniqueRTTI(CGM, Ty, Linkage);
> -  if (uniqueRTTI != UniqueRTTI) {
> +  CGCXXABI::RTTIUniquenessKind RTTIUniqueness =
> +      CGM.getCXXABI().classifyRTTIUniqueness(Ty, Linkage);
> +  if (RTTIUniqueness != CGCXXABI::RUK_Unique) {


This means that the flag is always set for arm64, right? If it is
always set, why is the flag needed?

Cheers,
Rafael