Bug 1603523 - [tryselect] Don't save fuzzy presets without a query, r=egao

Differential Revision: https://phabricator.services.mozilla.com/D56982

--HG--
extra : moz-landing-system : lando

tools/tryselect/mach_commands.py

@@ -303,6 +303,8 @@ class TrySelect(MachCommandBase):
             kwargs_copy['push'] = False
             kwargs_copy['save'] = None
             kwargs['query'] = self.run(save_query=True, **kwargs_copy)
+            if not kwargs['query']:
+                return
 
         if kwargs.get('paths'):
             kwargs['test_paths'] = kwargs['paths']