Commit 904a2018e0d3394ad91ffb6472f8271af7845295 introduced a new migration for
undecorated classes with decorated Angular class members. Currently the migration
always calls `tree.beginUpdate` and `tree.commitUpdate` (even if there are no changes).
This causes unnecessary updates to be reported to developers running `ng update`. Once
an update is commited, the CLI will report the update regardless of whether any changes were
made or not.
This behavior can be observed in the `ng_update_migrations` integration test. See:
https://circleci.com/gh/angular/angular/438470#tests/containers/3. Notice how all
source files are denoted as `UPDATED` (even though there are no changes).
PR Close#32391