errors: AssertionError moved to internal/error

AssertionError class is moved to interna/error
in reference to the TODO in assert.js. This was
suggested to get rid of the cyclic dependency
between assert.js and internal/error.js

PR-URL: https://github.com/nodejs/node/pull/12906
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/errors.js

@@ -41,6 +41,30 @@ function makeNodeError(Base) {
   };
 }
 
+class AssertionError extends Error {
+  constructor(options) {
+    if (typeof options !== 'object' || options === null) {
+      throw new exports.TypeError('ERR_INVALID_ARG_TYPE', 'options', 'object');
+    }
+    const util = lazyUtil();
+    const assert = lazyAssert();
+    const message = options.message ||
+                    `${util.inspect(options.actual).slice(0, 128)} ` +
+                    `${options.operator} ` +
+                    util.inspect(options.expected).slice(0, 128);
+
+    super(message);
+    this.generatedMessage = !options.message;
+    this.name = 'AssertionError [ERR_ASSERTION]';
+    this.code = 'ERR_ASSERTION';
+    this.actual = options.actual;
+    this.expected = options.expected;
+    this.operator = options.operator;
+    const stackStartFunction = options.stackStartFunction || assert.fail;
+    Error.captureStackTrace(this, stackStartFunction);
+  }
+}
+
 function message(key, args) {
   const assert = lazyAssert();
   assert.strictEqual(typeof key, 'string');
@@ -69,6 +93,7 @@ module.exports = exports = {
   Error: makeNodeError(Error),
   TypeError: makeNodeError(TypeError),
   RangeError: makeNodeError(RangeError),
+  AssertionError,
   E // This is exported only to facilitate testing.
 };