fix: strict type check for cross realms (#21669)

Deno v1.39 introduces `vm.runInNewContext`. This may cause problems when
using `Object.prototype.isPrototypeOf` to check built-in types.

```js
import vm from "node:vm";

const err = new Error();
const crossErr = vm.runInNewContext(`new Error()`);

console.assert( !(crossErr instanceof Error) );
console.assert( Object.getPrototypeOf(err) !== Object.getPrototypeOf(crossErr) );
```

This PR changes to check using internal slots solves them.

---

current: 

```
> import vm from "node:vm";
undefined
> vm.runInNewContext(`new Error("message")`)
Error {}
> vm.runInNewContext(`new Date("2018-12-10T02:26:59.002Z")`)
Date {}
```

this PR:

```
> import vm from "node:vm";
undefined
> vm.runInNewContext(`new Error("message")`)
Error: message
    at <anonymous>:1:1
> vm.runInNewContext(`new Date("2018-12-10T02:26:59.002Z")`)
2018-12-10T02:26:59.002Z
```

---------

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/ext/fetch/26_fetch.js b/ext/fetch/26_fetch.js
index 38605d5c9..b53013e49 100644
--- a/ext/fetch/26_fetch.js
+++ b/ext/fetch/26_fetch.js
@@ -51,7 +51,7 @@ const {
   StringPrototypeStartsWith,
   StringPrototypeToLowerCase,
   TypeError,
-  Uint8ArrayPrototype,
+  TypedArrayPrototypeGetSymbolToStringTag,
 } = primordials;
 
 const REQUEST_BODY_HEADER_NAMES = [
@@ -131,7 +131,7 @@ async function mainFetch(req, recursive, terminator) {
     const stream = req.body.streamOrStatic;
     const body = stream.body;
 
-    if (ObjectPrototypeIsPrototypeOf(Uint8ArrayPrototype, body)) {
+    if (TypedArrayPrototypeGetSymbolToStringTag(body) === "Uint8Array") {
       reqBody = body;
     } else if (typeof body === "string") {
       reqBody = core.encode(body);