Remove notify_new_nodes for the UniformSolver

[Whebon]

In the current implementation, the UniformSolver posts all possible LocalConstraints from scratch:

"""
    notify_new_nodes(node::AbstractRuleNode, path::Vector{Int})

Notify all grammar constraints about the `node` and its (grand)children
"""
function notify_new_nodes(solver::UniformSolver, node::AbstractRuleNode, path::Vector{Int})
    for (i, childnode) ∈ enumerate(get_children(node))
        notify_new_nodes(solver, childnode, push!(copy(path), i))
    end
    solver.path_to_node[path] = node
    solver.node_to_path[node] = path
    for c ∈ get_grammar(solver).constraints
        on_new_node(solver, c, path)
    end
end

on_new_node(solver, c, path) is responsible for creating a related local constraint.

Target implementation

UniformSolver is instantiated inside another search. The outer search already keeps track of a list of active local constraints. It would be more efficient to copy the list of active constraints from the outer solver instead of trying to post all constraints from scratch.

This can be achieved by accepting a Set{LocalConstraint} in the constructor of the UniformSolver.
And skipping posting new constraints (on_new_node(solver, c, path)).