Issue #2748553 by mikeryan: Remove unused migration template_test module

core/modules/migrate/tests/modules/template_test/migration_templates/migrate.migration.node_template.yml

-id: node_template
-label: Template test - node
-migration_tags:
-  - Template Test
-source:
-  plugin: empty
-process:
-  src: barfoo
-destination:
-  plugin: entity:node

core/modules/migrate/tests/modules/template_test/migration_templates/migrate.migration.other_template.yml

-id: other_template
-label: Template with a different tag
-migration_tags:
-  - Different Template Test
-source:
-  plugin: empty
-process:
-  src: raboof
-destination:
-  plugin: entity:user

core/modules/migrate/tests/modules/template_test/migration_templates/migrate.migration.url_template.yml

-id: url_template
-label: Template test - URL
-migration_tags:
-  - Template Test
-source:
-  plugin: empty
-process:
-  src: foobar
-destination:
-  plugin: url_alias

core/modules/migrate/tests/modules/template_test/template_test.info.yml

-name: 'Migration template test'
-type: module
-package: Testing
-version: VERSION
-core: 8.x