correctly test for error equality on jest (#11937)

* correctly test for error equality on jest

* adjust tests, change schemafetch error

* linting

* enforce matching `ApolloError` instances in tests everywhere

* size

* also always enforce stricter checks for `GraphQLError`

Author: phryneas

.changeset/early-tips-vanish.md

@@ -0,0 +1,5 @@
+---
+"@apollo/client": patch
+---
+
+`createSchemaFetch`: simulate serialized errors instead of an `ApolloError` instance