[clang] Clang trunk regression breaks SFINAE with zero-sized array template parameter

[forworldm]

#include <cstdint>
#include <cstddef>

template<int N> struct Foo {
    operator uint16_t() const noexcept requires(N == 2) {
        return 0;
    }

    template<int I = 0, char (*)[(N == 8) || (I & 0)] = nullptr>
    operator uint64_t() const noexcept {
        return 0;
    }
};

int main() {
    Foo<2> foo;
    std::size_t bar = foo;
    return bar;
}

clang emits: error: zero-length arrays are not permitted in C++.
Earlier versions of Clang (up to 21) compiled the same code without issues.
see godbolt

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: forworldm (forworldm)

```C++ #include <cstdint> #include <cstddef>

template<int N> struct Foo {
operator uint16_t() const noexcept requires(N == 2) {
return 0;
}

template<int I = 0, char (*)[(N == 8) || (I & 0)] = nullptr>
operator uint64_t() const noexcept {
    return 0;
}

};

int main() {
Foo<2> foo;
std::size_t bar = foo;
return bar;
}

clang emits: `error: zero-length arrays are not permitted in C++`.
Earlier versions of Clang (up to 21) compiled the same code without issues.
see [godbolt](https://godbolt.org/z/P67TaT1WP)
</details>