Add legacy_md5_buildpack_paths_enabled param

jobs/cloud_controller_ng/spec

@@ -1212,3 +1212,7 @@ properties:
   cc.update_metric_tags_on_rename:
     description: "Enable sending a Desired LRP update when an app is renamed"
     default: true
+
+  cc.legacy_md5_buildpack_paths_enabled:
+    description: "Enable legacy MD5 buildpack paths. If disabled, xxhash64 is used for calculating paths in buildpack image layers."
+    default: true

jobs/cloud_controller_ng/templates/cloud_controller_ng.yml.erb

@@ -522,3 +522,5 @@ threadpool_size: <%= p("cc.experimental.thin_server.thread_pool_size") %>
 default_app_lifecycle: buildpack
 custom_metric_tag_prefix_list: <%= p("cc.custom_metric_tag_prefix_list") %>
 update_metric_tags_on_rename: <%= p("cc.update_metric_tags_on_rename") %>
+
+legacy_md5_buildpack_paths_enabled: <%= p("cc.legacy_md5_buildpack_paths_enabled") %>

spec/cloud_controller_ng/cloud_controller_ng_spec.rb

@@ -592,7 +592,7 @@ module Test
             end
           end
 
-          describe  'max_total_results' do
+          describe 'max_total_results' do
             context "when 'cc.renderer.max_total_results' is set" do
               it 'renders max_total_results into the ccng config' do
                 merged_manifest_properties['cc'].store('renderer', { 'max_total_results' => 1000 })
@@ -608,6 +608,30 @@ module Test
               end
             end
           end
+
+          describe 'legacy_md5_buildpack_paths_enabled' do
+            context 'when legacy md5 buildpack paths are enabled' do
+              before do
+                merged_manifest_properties['cc']['legacy_md5_buildpack_paths_enabled'] = true
+              end
+
+              it 'renders the correct value into the ccng config' do
+                template_hash = YAML.safe_load(template.render(merged_manifest_properties, consumes: links))
+                expect(template_hash['legacy_md5_buildpack_paths_enabled']).to be(true)
+              end
+            end
+
+            context 'when legacy md5 buildpack paths are disabled' do
+              before do
+                merged_manifest_properties['cc']['legacy_md5_buildpack_paths_enabled'] = false
+              end
+
+              it 'renders the correct value into the ccng config' do
+                template_hash = YAML.safe_load(template.render(merged_manifest_properties, consumes: links))
+                expect(template_hash['legacy_md5_buildpack_paths_enabled']).to be(false)
+              end
+            end
+          end
         end
       end
     end