Fix flaky Parse.GeoPoint test.

[nlutsenko]

I finally caught a condition when this fails - turns out that this is impacted by a state overflow from previous test, where upsert one the collection finishes after we deleted everything, ending up creating another column with a double geo point.
This is a valid fix for everyone regardless, because we are starting promises that can mutate schema, but are responding back from the server before the operation finishes. This merely awaits on it, thus eliminating the possibility of any state overflows.
Validated a fix by running tests over 5k times :)

cc @flovilmart, @DrewGross

and newcomer - @mcdonamp (you complained about it when building GCS 😁 )

[codecov-io]

Current coverage is 90.92%

Merging #908 into master will not affect coverage as of 9a3a4c9

@@            master    #908   diff @@
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  Files           72      72       
  Stmts         4154    4155     +1
  Branches       861     861       
  Methods          0       0       
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+ Hit           3777    3778     +1
  Partial         10      10       
  Missed         367     367       

Review entire Coverage Diff as of 9a3a4c9

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[drew-gross]

Nice catch!