test(docs-infra): ensure examples are split correctly across shards (#46005)

Previously, the examples were split across shards based on the order in
which `globby()` returned them. This was based on the assumption that
`globby()`/the OS would list files in a deterministic order. However, it
turns out that examples can be listed in different orders between
executions, leading in them not being split correctly across shards on
CI (which further means that some examples may be tested multiple times
and others may not be tested at all).
You can see an example [here][1], where the `getting-started` example is
tested in both the 4th and 5th shards.

This commit fixes this by explicitly sorting the examples based on their
path.

[1]: https://circleci.com/gh/angular/angular/1165448

PR Close #46005

aio/tools/examples/run-example-e2e.mjs

@@ -417,6 +417,7 @@ function getE2eSpecsFor(basePath, specFile, filter) {
   return globby(e2eSpecGlob, {cwd: basePath, nodir: true})
       .then(
           paths => paths.filter(file => !IGNORED_EXAMPLES.some(ignored => file.startsWith(ignored)))
+                       .sort()
                        .map(file => path.join(basePath, file)));
 }