[clang] Claim conformance for CWG466 (#87748)

[CWG466](https://cplusplus.github.io/CWG/issues/466.html) "cv-qualifiers
on pseudo-destructor type".
Richard claimed that we don't implement this DR because of one
ill-formed example being accepted: `a->CI::~VI();`. This example is
testing the behavior of calling a pseudo-destructor via a qualified
name, where components of qualified name denote the same `int` type, but
with different cv-qualifications.

Initially, the following wording from [expr.pseudo] quoted in CWG466 was
left intact:
> Furthermore, the two type-names in a pseudo-destructor-name of the
form
>
>    `:: (opt) nested-name-specifier (opt) type-name ::~ type-name`
>
>shall designate the same scalar type.

According to this wording, the example is indeed ill-formed.

[P1131R2](https://wg21.link/p1131r2) merged wording for
pseudo-destructors into regular destructor wording. Among other things,
[expr.pseudo] was removed, and [expr.prim.id.qual]/2 was changed to
read:

> Whe...