Missing constraint error in instantiation expression for a nested class

### 🔎 Search Terms

instantiation expression caching class expression declaration type arguments type parameter

### 🕗 Version & Regression Information

- This changed in PR: https://github.com/microsoft/TypeScript/pull/59931 , cc @weswigham

### ⏯ Playground Link

https://www.typescriptlang.org/play/?ts=5.9.0-dev.20250701#code/MYGwhgzhAECCA8AVaBeaA7ArgWwEYFMAnAPmgG8AoaaANzBE3wEIAuaRAbiumAAsBLEABNW0AJLoIAFzDpg+RAE8ADvnhSV+APYAzOADoAQvASJi5jtAD0V6FIEwIvLZmHQihLYQrdpYKfzA0IaoPOBQwUjuAB5S+OhCMLChsKSU1NTKYITxUqKc3AC+XIUUQA

### 💻 Code

```ts
class A {
value!: T;
child!: InstanceType>>; // this should error

static B = class B {
parent!: T;
};
}
```

### 🙁 Actual behavior

It doesn't error

### 🙂 Expected behavior

it should error with:
```
Type 'A' does not satisfy the constraint 'A'.
Type 'T' is not assignable to type 'number'.(2344)
```

like it did in 5.6: [TS playground](https://www.typescriptlang.org/play/?ts=5.6.3#code/MYGwhgzhAECCA8AVaBeaA7ArgWwEYFMAnAPmgG8AoaaANzBE3wEIAuaRAbiumAAsBLEABNW0AJLoIAFzDpg+RAE8ADvnhSV+APYAzOADoAQvASJi5jtAD0V6FIEwIvLZmHQihLYQrdpYKfzA0IaoPOBQwUjuAB5S+OhCMLChsKSU1NTKYITxUqKc3AC+XIUUQA)

### Additional information about the issue

The problem here is that the situation is a little bit circular and variances worker gets hits in reentrant manner. The nested call returns `emptyArray` that is a signal for `structuredTypeRelatedToWorker` to return `Ternary.Unknown`.

So `checkTypeArguments` called by `getInstantiatedSignatures` doesn't report an error. In the old version of the code, this would be re-called after the variance worker would completely exit and the error would be raised.

I see 2 ways to solve this:
- ignore the introduced caching based `inVarianceComputation` to avoid spoiling this
- defer `checkTypeArguments` in `getInstantiatedSignatures` (well, call it with `/*reportErrors*/ false` and defer anoher call with `/*reportErrors*/ true`)

Start with the linked TypeScript Playground repro and trace getInstantiatedSignatures through checkTypeArguments, structuredTypeRelatedToWorker, and the inVarianceComputation path. Compare behavior with the 5.6 Playground link and determine how the deferred or uncached check should report the constraint error. Done means the current repro produces diagnostic 2344 without breaking related type-checking behavior.

Written by the indexing model from the issue text.