[clang] [clang][Interp] Only evaluate the source array initialization of an `ArrayInitLoopExpr` once (PR #68039)

[Timm Baeder via cfe-commits]

================
@@ -366,8 +363,7 @@ namespace ArrayInitLoop {
       auto [a, b, c] = f(n).arr;
       return a + b + c;
   }
-  static_assert(g() == 6); // expected-error {{failed}} \
-                           // expected-note {{15 == 6}}
+  static_assert(g() == 6);
----------------
tbaederr wrote:

```suggestion
  static_assert(g() == 6, "");
```

https://github.com/llvm/llvm-project/pull/68039