Pass calling scope to stdlib::ensure_packages from shim

Make the `ensure_packages` shim an Internal function and pass scope to
the namespaced version so as to not change the behaviour of where
packages are contained.

When the function was first ported to the new API, it was discussed that
the existing behaviour might not be 'correct', but changing it would be
a breaking change that might have consequences for many users.

In namespacing the function in 9.0.0 we accidentally created a situation
where the namespaced version worked as before, but the non-namespaced
version, (the shim), now behaved differently.

Fixes #1365

Rakefile

@@ -92,11 +92,16 @@ task :regenerate_unamespaced_shims do
   Dir['lib/puppet/functions/*.rb'].each do |filename|
     content = File.read(filename)
 
-    unless content =~ /@summary DEPRECATED.  Use the namespaced function/
+    unless content =~ /@summary DEPRECATED\.  Use the namespaced function/
       warn("#{filename} does not look like a deprecation shim (skipping)")
       next
     end
 
+    if content =~ /InternalFunction/
+      warn("#{filename} is a special case. Not regenerating a shim for this file")
+      next
+    end
+
     function_name = File.basename(filename, '.rb')
 
     File.write(filename, <<~CODE)

lib/puppet/functions/ensure_packages.rb

@@ -1,14 +1,13 @@
 # frozen_string_literal: true
 
-# THIS FILE WAS GENERATED BY `rake regenerate_unamespaced_shims`
-
 # @summary DEPRECATED.  Use the namespaced function [`stdlib::ensure_packages`](#stdlibensure_packages) instead.
-Puppet::Functions.create_function(:ensure_packages) do
+Puppet::Functions.create_function(:ensure_packages, Puppet::Functions::InternalFunction) do
   dispatch :deprecation_gen do
+    scope_param
     repeated_param 'Any', :args
   end
-  def deprecation_gen(*args)
+  def deprecation_gen(scope, *args)
     call_function('deprecation', 'ensure_packages', 'This function is deprecated, please use stdlib::ensure_packages instead.')
-    call_function('stdlib::ensure_packages', *args)
+    scope.call_function('stdlib::ensure_packages', args)
   end
 end