Add initial test files from lodash v4. (#4172)

* Install test dependencies.

* Add initial test files.

These files were created using a simplistic AST manipulator using `recast` to
preserve formatting. There's bound to be a huge chunk of errors, but this serves
as a good start. QUnit was replaced with Mocha, with ES2015 imports running via
`esm`.

As far as possible, QUnit-specific syntax has been replaced with Mocha's
`describe` and `it`, while the native Node.js `assert` module is used for
assertions. Files in the `test` directory ending in `.test.js` will be treated
as test files.

* Add initial passing files to test run.

package-lock.json

@@ -1228,6 +1228,12 @@
         "repeat-element": "^1.1.2"
       }
     },
+    "browser-stdout": {
+      "version": "1.3.1",
+      "resolved": "https://registry.npmjs.org/browser-stdout/-/browser-stdout-1.3.1.tgz",
+      "integrity": "sha512-qhAVI1+Av2X7qelOfAIYwXONood6XlZE/fXaBSmW/T5SzLAmCgzi+eiWE7fUvbHaeNBQH13UftjpXxsfLkMpgw==",
+      "dev": true
+    },
     "browserify-aes": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/browserify-aes/-/browserify-aes-0.4.0.tgz",
@@ -1877,6 +1883,12 @@
         "repeating": "^2.0.0"
       }
     },
+    "diff": {
+      "version": "3.5.0",
+      "resolved": "https://registry.npmjs.org/diff/-/diff-3.5.0.tgz",
+      "integrity": "sha512-A46qtFgd+g7pDZinpnwiRJtxbC1hpgf0uzP3iG89scHk0AUC7A1TGxf5OiiOUv/JMZR8GOt8hL900hV0bOy5xA==",
+      "dev": true
+    },
     "docdown": {
       "version": "0.7.3",
       "resolved": "https://registry.npmjs.org/docdown/-/docdown-0.7.3.tgz",
@@ -2252,6 +2264,12 @@
         }
       }
     },
+    "esm": {
+      "version": "3.1.3",
+      "resolved": "https://registry.npmjs.org/esm/-/esm-3.1.3.tgz",
+      "integrity": "sha512-W5DKpMvvvtdn4Wzwl9scBUlsdiy4sXALG5oKIrCgnalg6db6vAztKVHWfOW4R8TlFvXlZDjipXSTrqhJDHpdRg==",
+      "dev": true
+    },
     "espree": {
       "version": "3.5.4",
       "resolved": "http://backoffice-npm-proxy.prod:4873/espree/-/espree-3.5.4.tgz",
@@ -3209,6 +3227,12 @@
       "integrity": "sha1-TK+tdrxi8C+gObL5Tpo906ORpyU=",
       "dev": true
     },
+    "growl": {
+      "version": "1.10.5",
+      "resolved": "https://registry.npmjs.org/growl/-/growl-1.10.5.tgz",
+      "integrity": "sha512-qBr4OuELkhPenW6goKVXiv47US3clb3/IbuWF9KNKEijAy9oeHxU9IgzjvJhHkUzhaj7rOUD7+YGWqUjLp5oSA==",
+      "dev": true
+    },
     "handlebars": {
       "version": "4.0.11",
       "resolved": "https://registry.npmjs.org/handlebars/-/handlebars-4.0.11.tgz",
@@ -4154,6 +4178,51 @@
         }
       }
     },
+    "mocha": {
+      "version": "5.2.0",
+      "resolved": "https://registry.npmjs.org/mocha/-/mocha-5.2.0.tgz",
+      "integrity": "sha512-2IUgKDhc3J7Uug+FxMXuqIyYzH7gJjXECKe/w43IGgQHTSj3InJi+yAA7T24L9bQMRKiUEHxEX37G5JpVUGLcQ==",
+      "dev": true,
+      "requires": {
+        "browser-stdout": "1.3.1",
+        "commander": "2.15.1",
+        "debug": "3.1.0",
+        "diff": "3.5.0",
+        "escape-string-regexp": "1.0.5",
+        "glob": "7.1.2",
+        "growl": "1.10.5",
+        "he": "1.1.1",
+        "minimatch": "3.0.4",
+        "mkdirp": "0.5.1",
+        "supports-color": "5.4.0"
+      },
+      "dependencies": {
+        "debug": {
+          "version": "3.1.0",
+          "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
+          "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+          "dev": true,
+          "requires": {
+            "ms": "2.0.0"
+          }
+        },
+        "has-flag": {
+          "version": "3.0.0",
+          "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-3.0.0.tgz",
+          "integrity": "sha1-tdRU3CGZriJWmfNGfloH87lVuv0=",
+          "dev": true
+        },
+        "supports-color": {
+          "version": "5.4.0",
+          "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-5.4.0.tgz",
+          "integrity": "sha512-zjaXglF5nnWpsq470jSv6P9DwPvgLkuapYmfDm3JWOm0vkNTVF2tI4UrN2r6jH1qM/uc/WtxYY1hYoA2dOKj5w==",
+          "dev": true,
+          "requires": {
+            "has-flag": "^3.0.0"
+          }
+        }
+      }
+    },
     "ms": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",