Adding npm package co to run legacy tests

Author: kiwiupover

packages/ember-cli-fastboot/package.json

@@ -46,6 +46,7 @@
     "body-parser": "^1.18.3",
     "broccoli-asset-rev": "^3.0.0",
     "broccoli-test-helper": "^1.5.0",
+    "co": "4.6.0",
     "chai": "^4.1.2",
     "chai-fs": "^2.0.0",
     "chai-string": "^1.4.0",

yarn.lock

@@ -5577,6 +5577,11 @@ clone@^2.0.0, clone@^2.1.2:
   resolved "https://registry.yarnpkg.com/clone/-/clone-2.1.2.tgz#1b7f4b9f591f1e8f83670401600345a02887435f"
   integrity sha1-G39Ln1kfHo+DZwQBYANFoCiHQ18=
 
+co@4.6.0:
+  version "4.6.0"
+  resolved "https://registry.yarnpkg.com/co/-/co-4.6.0.tgz#6ea6bdf3d853ae54ccb8e47bfa0bf3f9031fb184"
+  integrity sha1-bqa989hTrlTMuOR7+gvz+QMfsYQ=
+
 code-point-at@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/code-point-at/-/code-point-at-1.1.0.tgz#0d070b4d043a5bea33a2f1a40e2edb3d9a4ccf77"