Fix bug that user-provided context is lost if skip is toggled

[chochihim]

I am not sure if this is the best fix and how test should be added for this case. Let me know and I can change the code accordingly.

Checklist:

• If this PR is a new feature, please reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests

[apollo-cla]

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[benjamn]

@chochihim We ended up reverting the deletion of observableQuery.options.context in tearDownQuery in #7695. Is this change still relevant now?

[chochihim]

It should be fine now. I will open another issue if I still encounter my problem using the latest version.