Allow single server instance in test suite (#7262)

* initial pass

* reconfigureServer when needed

* finish postgres tests

* mongo tests

* more tests

* clean up

* re-add skipped test

* Fix transaction tests

* handle batch

* AuthenticationAdapter fix

* More reconfiguration

* clean up

* properly terminate cli servers

* handle Parse.Push

* Flaky PushController

* ensure reconfigureServer when changed

* fix postgres tests

* remove console.log

* LiveQuery spec remove duplicates and listeners

spec/CLI.spec.js

@@ -209,8 +209,12 @@ describe('execution', () => {
   const binPath = path.resolve(__dirname, '../bin/parse-server');
   let childProcess;
 
-  afterEach(async () => {
+  afterEach(done => {
     if (childProcess) {
+      childProcess.on('close', () => {
+        childProcess = undefined;
+        done();
+      });
       childProcess.kill();
     }
   });