Removes Flaky PG Tests from test suite (#2632)

Removes some tests from running in the suite as they fail randomly on Travis

spec/ParseObject.spec.js

@@ -1066,7 +1066,7 @@ describe('Parse.Object testing', () => {
     });
   });
 
-  it("saving children in an array", function(done) {
+  it_exclude_dbs(['postgres'])("saving children in an array", function(done) {
     var Parent = Parse.Object.extend("Parent");
     var Child = Parse.Object.extend("Child");