Remote resolver (microsoft#21332)

This is branch will serve as a feature branch for all changes related to
switching to the remote resolver.
This will include
- switching from using the testAdapter to parse the return data to now
using this new class resultResolver
- adding tests for all testAdapters, fixing for server and adding for
resultResolver
- moving sendCommand to a new file, out of the server, and getting
pytest to adopt it
- moving the server which send the test IDs to a new file and adopt it
for both pytest and unittest
- write tests for these two new files.

src/client/testing/testController/unittest/testExecutionAdapter.ts

@@ -4,7 +4,7 @@
 import * as path from 'path';
 import { TestRun, Uri } from 'vscode';
 import { IConfigurationService, ITestOutputChannel } from '../../../common/types';
-import { createDeferred, Deferred } from '../../../common/utils/async';
+import { Deferred, createDeferred } from '../../../common/utils/async';
 import { EXTENSION_ROOT_DIR } from '../../../constants';
 import {
     DataReceivedEvent,