Stop setting potentially non-string name properties on Errors (#2963)

For example, extractError in query.js, when given a bare (bodyless)
response, will pass the (numeric) httpResponse statusCode as the
`code` option to util.error. util.error then sets the `name` property
of the Error from this. The result is that property ends up as a number,
but is required to a string; nodejs calls endsWith() on it
https://github.com/nodejs/node/blob/e5d3c8121dd0bcc4dbf52c7b3a0521e359363a05/lib/internal/util/inspect.js#L922
, so will throw an exception if an Error with a non-string name is
ever inspected.

.changes/next-release/bugfix-util-358e56d3.json

@@ -0,0 +1,5 @@
+{
+  "type": "bugfix",
+  "category": "util",
+  "description": "Fix `name.endsWith is not a function` exception when inspecting some generated errors with some versions of nodejs"
+}

lib/util.js

@@ -594,7 +594,7 @@ var util = {
       Object.defineProperty(err, 'message', {enumerable: true});
     }
 
-    err.name = options && options.name || err.name || err.code || 'Error';
+    err.name = String(options && options.name || err.name || err.code || 'Error');
     err.time = new Date();
 
     if (originalError) err.originalError = originalError;