tests: Do not use compression in tar assembler

XZ compression is really slowing down our tests. Additionally, we dump
the resulting image right after the tests are done (at least on CI).
Let's just dump the compression.

test/__main__.py

@@ -58,7 +58,7 @@ if __name__ == '__main__':
         name="timezone",
         pipeline="timezone.json",
         build_pipeline=args.build_pipeline,
-        output_image="timezone.tar.xz",
+        output_image="timezone.tar",
         test_cases=[test_timezone],
         type=IntegrationTestType.EXTRACT
     )
@@ -66,7 +66,7 @@ if __name__ == '__main__':
         name="firewall",
         pipeline="firewall.json",
         build_pipeline=args.build_pipeline,
-        output_image="firewall.tar.xz",
+        output_image="firewall.tar",
         test_cases=[test_firewall],
         type=IntegrationTestType.EXTRACT
     )
@@ -74,7 +74,7 @@ if __name__ == '__main__':
         name="locale",
         pipeline="locale.json",
         build_pipeline=args.build_pipeline,
-        output_image="locale.tar.xz",
+        output_image="locale.tar",
         test_cases=[test_locale],
         type=IntegrationTestType.EXTRACT
     )

test/pipelines/firewall.json

@@ -27,8 +27,7 @@
   "assembler": {
     "name": "org.osbuild.tar",
     "options": {
-      "filename": "firewall.tar.xz",
-      "compression": "xz"
+      "filename": "firewall.tar"
     }
   }
 }

test/pipelines/locale.json

@@ -25,8 +25,7 @@
   "assembler": {
     "name": "org.osbuild.tar",
     "options": {
-      "filename": "locale.tar.xz",
-      "compression": "xz"
+      "filename": "locale.tar"
     }
   }
 }

test/pipelines/timezone.json

@@ -25,8 +25,7 @@
   "assembler": {
     "name": "org.osbuild.tar",
     "options": {
-      "filename": "timezone.tar.xz",
-      "compression": "xz"
+      "filename": "timezone.tar"
     }
   }
 }