treemap: add new API `ReverseRange` for iterating TreeMap in Reverse Order

[wenchy]

Refer to the similar API Range:

loader/pkg/treemap/custom.go

Lines 82 to 91 in 9387b01

	// Range calls f sequentially for each key and value present in the map.
	// If f returns false, range stops the iteration.
	func (m *TreeMap[K, V]) Range(f func(key K, value V) bool) {
	iterator := m.Iterator()
	for iterator.Next() {
	if !f(iterator.Key(), iterator.Value()) {
	break
	}
	}
	}