when a transaction is interrupted, Pool error BadResource: Bad resource ID

Use the following code to test, there is a certain probability of problems. (使用以下代码测试, 有一定概率出现问题)

```ts
import * as postgres from 'https://deno.land/x/postgres@v0.15.0/mod.ts';

const pool2 = new postgres.Pool(databaseUrl, 2, true);

Deno.test('pool-error', async () => {
const p1 = (async () => {
const c = await pool2.connect();
console.log('p1', c.connected);
try {
const t = c.createTransaction('p1-t');
await t.begin();
t.queryArray(
`INSERT INTO test_table ("at") VALUES ($1);`,
[new Date().toString() + 'p1'],
);
throw new Error('some error');
} finally {
c.release();
}
})().catch((err) => {
console.error('p1', err);
});

const p2 = (async () => {
const c = await pool2.connect();
console.log('p2', c.connected);
try {
const t = c.createTransaction('p2-t');
await t.begin();
t.queryArray(
`INSERT INTO test_table ("at") VALUES ($1);`,
[new Date().toString() + 'p2'],
);
await t.commit();
} finally {
c.release();
}
})().catch((err) => {
console.error('p2', err);
});

try {
await Promise.all([p1, p2]);
} finally {
await pool2.end();
}
});
```

The error info is: (出现的错误为)

```
BadResource: Bad resource ID
rr = await this.rd.read(this.buf);
^
at async read (deno:ext/net/01_net.js:24:19)
at async BufReader.read (https://deno.land/std@0.114.0/io/buffer.ts:383:12)
at async BufReader.readFull (https://deno.land/std@0.114.0/io/buffer.ts:415:20)
at async Connection.#readMessage (https://deno.land/x/postgres@v0.15.0/connection/connection.ts:152:5)
at async Connection.#preparedQuery (https://deno.land/x/postgres@v0.15.0/connection/connection.ts:853:27)
at async Connection.query (https://deno.land/x/postgres@v0.15.0/connection/connection.ts:930:16)
at async Transaction.queryArray (https://deno.land/x/postgres@v0.15.0/query/transaction.ts:413:14)
```

This problem does not occur if `catch (err) {
await t.rollback();
throw err;
}` is done in the above code.