test(i): Update mut. tests to make use of mut. system (#1853)

## Relevant issue(s)

Resolves #1851

## Description

Updates the mutation tests to make use of mutation system.

A handful of collection based tests still exist, as they test stuff that
does not yet have support in the new mutation test system (filter,
UpdateWithKey(s)). These should be moved later when such support is
added.

Similarly, the new mutation system does not yet support txns, so the gql
request based txn tests remain as gql tests for now.

#1703 Was linked up to
tests in this PR, and
#1852 and
#1854 were discovered.
Fixing them is out of scope here.

Update: It does now fix a bug in the http client collection.Create[Many]
functions, as it was easier to fix than to open a ticket.

docs/data_format_changes/i1851-no-change-tests-updated.md

@@ -0,0 +1,3 @@
+# Make existing mutation tests use mutation test system
+
+This is not a breaking change, tests were changed from using gql requests to CreateDoc and UpdateDoc actions, meaning the point at which the change detector split setup/assert shifted.

http/client_collection.go

@@ -58,6 +58,13 @@ func (c *Collection) SchemaID() string {
 func (c *Collection) Create(ctx context.Context, doc *client.Document) error {
 	methodURL := c.http.baseURL.JoinPath("collections", c.desc.Name)
 
+	// We must call this here, else the doc key on the given object will not match
+	// that of the document saved in the database
+	err := doc.RemapAliasFieldsAndDockey(c.Description().Schema.Fields)
+	if err != nil {
+		return err
+	}
+
 	body, err := doc.String()
 	if err != nil {
 		return err
@@ -79,6 +86,13 @@ func (c *Collection) CreateMany(ctx context.Context, docs []*client.Document) er
 
 	var docMapList []json.RawMessage
 	for _, doc := range docs {
+		// We must call this here, else the doc key on the given object will not match
+		// that of the document saved in the database
+		err := doc.RemapAliasFieldsAndDockey(c.Description().Schema.Fields)
+		if err != nil {
+			return err
+		}
+
 		docMap, err := documentJSON(doc)
 		if err != nil {
 			return err