Currently, if you use axios with async / await, you get a stack trace like this:

```
Request failed with status code 500
    at createError (/Users/rmenezes/code/seedfi/web/node_modules/axios/lib/core/createError.js:16:15)
    at settle (/Users/rmenezes/code/seedfi/web/node_modules/axios/lib/core/settle.js:17:12)
    at IncomingMessage.handleStreamEnd (/Users/rmenezes/code/seedfi/web/node_modules/axios/lib/adapters/http.js:237:11)
    at IncomingMessage.emit (events.js:208:15)
    at IncomingMessage.EventEmitter.emit (domain.js:471:20)
    at endReadableNT (_stream_readable.js:1154:12)
    at processTicksAndRejections (internal/process/task_queues.js:77:11
```

It doesn't show you much about *what* called Axios., which makes debugging quite difficult!

This is because `settle` calls `createError`:
https://github.com/axios/axios/blob/master/lib/core/settle.js#L12-L24

Which creates a new error with a brand new stack trace:
https://github.com/axios/axios/blob/master/lib/core/createError.js#L15-L18

Perhaps we can fix this by creating an error before the request goes out and stitching it to the new error's stack trace?
test/unit/adapters/http.js
server = await startHTTPServer(async (req, res) => {
              res.setHeader('Content-Encoding', type);
              res.end(await zipped);
            });
            const {data} = await axios.get(LOCAL_SERVER_URL);
            assert.strictEqual(data, responseBody);
          });
          it(`should not fail if response content-length header is missing (${type})`, async () => {
            server = await startHTTPServer(async (req, res) => {
              res.setHeader('Content-Encoding', type);
              res.removeHeader('Content-Length');
              res.end(await zipped);
            });
            const {data} = await axios.get(LOCAL_SERVER_URL);
            assert.strictEqual(data, responseBody);
          });
          it('should not fail with chunked responses (without Content-Length header)', async () => {
            server = await startHTTPServer(async (req, res) => {
              res.setHeader('Content-Encoding', type);
              res.setHeader('Transfer-Encoding', 'chunked');
              res.removeHeader('Content-Length');
              res.write(await zipped);
              res.end();
            });
            const {data} = await axios.get(LOCAL_SERVER_URL);
            assert.strictEqual(data, responseBody);
          });
          it('should not fail with an empty response without content-length header (Z_BUF_ERROR)', async () => {
            server = await startHTTPServer((req, res) => {
              res.setHeader('Content-Encoding', type);