Refactor the usage of batch catfile (#31754)

When opening a repository, it will call `ensureValidRepository` and also
`CatFileBatch`. But sometimes these will not be used until repository
closed. So it's a waste of CPU to invoke 3 times git command for every
open repository.

This PR removed all of these from `OpenRepository` but only kept
checking whether the folder exists. When a batch is necessary, the
necessary functions will be invoked.

modules/git/commit_info_nogogit.go

@@ -124,7 +124,10 @@ func GetLastCommitForPaths(ctx context.Context, commit *Commit, treePath string,
 		return nil, err
 	}
 
-	batchStdinWriter, batchReader, cancel := commit.repo.CatFileBatch(ctx)
+	batchStdinWriter, batchReader, cancel, err := commit.repo.CatFileBatch(ctx)
+	if err != nil {
+		return nil, err
+	}
 	defer cancel()
 
 	commitsMap := map[string]*Commit{}