[migration/3.18] disable all hooks when setting up symmetric relations This operation is semantically a no-op, so it should be invisible for the application. Related to #3259713.

[devtools] bases for instrumenting / debugging standard propagation hooks * a class that helps writing command to check propagation, detecting standard errors and picture the propagation as a graph * a class to instrument sets used to configure standard propagation hooks closes #3171980

instrument cwvreg, so we may know what's being loaded by asking the registry store