Change how unit tests are set up and run

Moves init.test.el to core/test/init.el and initializes the test
environment from within the current session, rather than through a bash
script middle man.

TODO: don't buffer the unit test results

core/test/init.el

@@ -0,0 +1,17 @@
+;;; core/test/init.el -*- lexical-binding: t; no-byte-compile: t; -*-
+
+;; An init.el for our unit test suites. Do not use this!
+
+(doom! :completion
+       company
+       :ui
+       doom-dashboard
+       popup
+       workspaces
+       :editor
+       evil
+       :tools
+       pass
+       :lang
+       org
+       web)