enhance: Add tests for premature caching of contextual parameter types

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### Comment

Add tests for premature caching of contextual parameter types

The checker currently handles the following code correctly.

But the existing cases in `contextuallyTypedParametersWithInitializers2.ts` do not appear to cover the following case: the combination of premature type caching and parameter whose type is widened during contextual checking.

**Example:**

It is ok:

```ts
const fn: (reader: () => number, value: 1) => void =
(get = () => x, x = 0) => {
x.toFixed();
};
```
**Why this needs regression coverage:**

when caching the symbol type, we need to check if it is context sensitive, as the author intentionly said:
```go
func (c *Checker) getTypeOfVariableOrParameterOrProperty(symbol *ast.Symbol) *Type {
links := c.valueSymbolLinks.Get(symbol)
if links.resolvedType == nil {
t := c.getTypeOfVariableOrParameterOrPropertyWorker(symbol)
if t == nil {
panic("Unexpected nil type")
}
// For a contextually typed parameter it is possible that a type has already
// been assigned (in assignTypeToParameterAndFixTypeParameters), and we want
// to preserve this type. In fact, we need to _prefer_ that type, but it won't
// be assigned until contextual typing is complete, so we need to defer in
// cases where contextual typing may take place.
if links.resolvedType == nil && !c.isParameterOfContextSensitiveSignature(symbol) {
links.resolvedType = t
}
return t
}
return links.resolvedType
}
```

Checking `get = () => x` queries `x` before its contextual parameter checking is complete:

1. The initial query get the contextual type `1`.
2. Later, checking the default value `0` and widens the parameter's type to `number`.
3. If the initial result `1` is cached, `assignParameterType` returns early and cannot assign the final type.

This would incorrectly produce the error:

```text
Type '0' is not assignable to type '1'.
```

The existing guard in `getTypeOfVariableOrParameterOrProperty` prevents this premature caching:

```go
!c.isParameterOfContextSensitiveSignature(symbol)
```

The example passes with the current implementation. Removing the guard will produce the incorrect TS2322 diagnostic.

**Proposed change:**

Just add this case to `contextuallyTypedParametersWithInitializers2.ts`

```ts
const test4: (reader: () => number, value: 1) => void =
(get = () => x, x = 0) => {
x.toFixed();
};
```
Add this case to the contextual parameter initializer tests, together with type and symbol baselines, to protect the existing behavior against regressions.

Existing tests cover the caching guard’s effect on implicit any diagnostics. This test adds coverage of type widening for parameters with default initializers, ensuring that prematurely cached literal types do not cause spurious errors.

Inizia con contextuallyTypedParametersWithInitializers2.ts e con i casi esistenti degli inizializzatori di parametri contestuali, quindi esegui i test del compilatore associati. Aggiungi il caso proposto test4 e aggiorna le baseline dei tipi e dei simboli. Il lavoro è completato quando il test passa con l’attuale guardia della cache e non produce la diagnosi spur ia TS2322.

Scritto dal modello di indicizzazione a partire dal testo della issue.