Previously we had a singleton `ROOT_SCOPE` object, from
which all `BindingScope`s derived. But this caused ngcc to
produce non-deterministic output when running multiple workers
in parallel, since each process had its own `ROOT_SCOPE`.
In reality there is no need for `BindingScope` reference names
to be unique across an entire application (or in the case of ngcc
across all the libraries). Instead we just need uniqueness within
a template.
This commit changes the compiler to create a new root `BindingScope`
each time it compiles a component's template.
Resolves#35180
PR Close#36362
e526f74dfd