Add exception for failed post.

If post fails, raise exception which will kill test run.

Bug: 1096591
Change-Id: I1a6ed12540b356965e5f74314de31cab4b9b36f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442898Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Reviewed-by: Peter Wen <wnwen@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813332}

build/android/pylib/base/result_sink.py

@@ -94,6 +94,7 @@ class ResultSinkClient(object):
     if len(test_log) > report_check_size:
       tr['artifacts'] = {'Test Log': {'contents': base64.b64encode(test_log)}}
 
-    requests.post(url=self.url,
-                  headers=self.headers,
-                  data=json.dumps({'testResults': [tr]}))
+    res = requests.post(url=self.url,
+                        headers=self.headers,
+                        data=json.dumps({'testResults': [tr]}))
+    res.raise_for_status()