PYTHON-4478 Use single mongos in racy unacknowledged write tests (mongodb#1764)

Author: blink1073

test/command_logging/unacknowledged-write.json

@@ -5,6 +5,7 @@
     {
       "client": {
         "id": "client",
+        "useMultipleMongoses": false,
         "observeLogMessages": {
           "command": "debug"
         }

test/command_monitoring/unacknowledgedBulkWrite.json

@@ -5,6 +5,7 @@
     {
       "client": {
         "id": "client",
+        "useMultipleMongoses": false,
         "observeEvents": [
           "commandStartedEvent",
           "commandSucceededEvent",
@@ -70,17 +71,7 @@
           "object": "collection",
           "arguments": {
             "filter": {}
-          },
-          "expectResult": [
-            {
-              "_id": 1,
-              "x": 11
-            },
-            {
-              "_id": "unorderedBulkWriteInsertW0",
-              "x": 44
-            }
-          ]
+          }
         }
       ],
       "expectEvents": [

test/command_monitoring/writeConcernError.json

@@ -152,4 +152,4 @@
       ]
     }
   ]
-}
+}