Don't read from cache when fetchPolicy = 'no-cache'

[onethread]

Migrated from: apollographql/apollo-client#3396:

I have a lot of large read-only queries that I am using fetchPolicy='no-cache', but through the vue-apollo bindings the getCurrentQueryResult function is used in certain contexts that do a lot of unnecessary work / exceptions being thrown and caught that show up in my profiling analysis.

At this line, it should be safe to no execute this.dataStore.getCache().read(...) if observableQuery.options.fetchPolicy = 'no-cache' since our store will never contain this query.

Probably short-circuiting the function and returning: return maybeDeepFreeze({ data: {}, partial: true }); would be best.

https://github.com/apollographql/apollo-client/blob/9ac90e0c1729d11a41663c9a7032200369f3305d/packages/apollo-client/src/core/QueryManager.ts#L976