Catch unexpected http uri error in service isolate

Fixes #24388

[email protected]

Review URL: https://codereview.chromium.org//1357023004 .

Author: johnmccutchan

runtime/bin/vmservice/server.dart

@@ -146,9 +146,16 @@ class Server {
       return;
     }
     // HTTP based service request.
-    var client = new HttpRequestClient(request, _service);
-    var message = new Message.fromUri(client, request.uri);
-    client.onMessage(null, message);
+    try {
+      var client = new HttpRequestClient(request, _service);
+      var message = new Message.fromUri(client, request.uri);
+      client.onMessage(null, message);
+    } catch (e) {
+      print('Unexpected error processing HTTP request uri: '
+            '${request.uri}\n$e\n');
+      rethrow;
+    }
+
   }
 
   Future startup() {