When the nodes.VariableRefAttributeAccess and nodes.VariableRefMethodCall were added, the
node comparison function were broken since the class instances are not the same.
This is a problem when using the groupby and an attribute access or method call on projection
variable.
For example:
Any X, S.download_url() GROUPBY X,S WHERE X is ImportProcess, X shacl_report S

were a bad rql query since `S.download_url()` is not the same node (not the same class) as `S`.
But actually it is.

This patch allow this syntax

When the nodes.VariableRefAttributeAccess and nodes.VariableRefMethodCall were added, the
node comparison function were broken since the class instances are not the same.
This is a problem when using the groupby and an attribute access or method call on projection
variable.
For example:
Any X, S.download_url() GROUPBY X,S WHERE X is ImportProcess, X shacl_report S

were a bad rql query since `S.download_url()` is not the same node (not the same class) as `S`.
But actually it is.

This patch allow this syntax