readFile() and readFileSync() output don't match

The reproduction code is below.
This is happening in 0.41.3, but also in previous versions.

mod.js
```
export function check(uint8array) {
console.log(uint8array.buffer);
}
```

test.js
```
import { check } from "./mod.js";

Deno.test("readFileSync", () => {
const uint8array = Deno.readFileSync("file");
check(uint8array);
});
Deno.test("readFile", async () => {
const uint8array = await Deno.readFile("file");
check(uint8array);
});
```

deno run -A build_npm.js
```
Running tests in ./esm/test.js...

test readFileSync ...ArrayBuffer {
[Uint8Contents]: <2f 00 00 00 00 00 00 00 00 01 00 00 00 0b 00 80 00 03 00 30 47 53 55 42 20 8b 25 7a 00 00 01 38 00 00 00 54 4f 53 2f 32 38 3e 45 89 00 00 01 8c 00 00 00 60 63 6d 61 70 e9 b2 bd 48 00 00 01 f4 00 00 01 70 67 6c 79 66 bb e0 8f 70 00 00 03 6c 00 00 00 50 68 65 61 64 25 2b ff 77 00 00 00 e0 00 00 00 36 ... 8092 more bytes>,
byteLength: 8192
}
test readFile ...ArrayBuffer {
[Uint8Contents]: <00 01 00 00 00 0b 00 80 00 03 00 30 47 53 55 42 20 8b 25 7a 00 00 01 38 00 00 00 54 4f 53 2f 32 38 3e 45 89 00 00 01 8c 00 00 00 60 63 6d 61 70 e9 b2 bd 48 00 00 01 f4 00 00 01 70 67 6c 79 66 bb e0 8f 70 00 00 03 6c 00 00 00 50 68 65 61 64 25 2b ff 77 00 00 00 e0 00 00 00 36 68 68 65 61 03 d6 02 03 ... 1580 more bytes>,
byteLength: 1680
}
```
Only the result of `readFile()` is correct.
I know the following workaround, but I don't want to use it because it involves memory copying.

```
export function check(uint8array) {
const arrayBuffer = uint8array.buffer.slice(
uint8array.byteOffset,
uint8array.byteOffset + uint8array.byteLength
);
console.log(arrayBuffer);
}
```