Autopkgtest tests: Publish test packages on all architectures by default

This is a prerequisite for introducing per-architecture test calculation.

tests/__init__.py

@@ -78,7 +78,7 @@ class TestData:
         assert (name not in self.added_binaries[unstable])
         self.added_binaries[unstable].add(name)
 
-        fields.setdefault('Architecture', architectures[0])
+        fields.setdefault('Architecture', 'all')
         fields.setdefault('Version', '1')
         fields.setdefault('Priority', 'optional')
         fields.setdefault('Section', 'devel')

tests/test_autopkgtest.py

@@ -59,7 +59,6 @@ class TestAutoPkgTest(TestBase):
         self.data.add('blue', False, {'Depends': 'libc6 (>= 0.9)',
                                       'Conflicts': 'green'},
                       testsuite='specialtest')
-        self.data.add('justdata', False, {'Architecture': 'all'})
 
         # create mock Swift server (but don't start it yet, as tests first need
         # to poke in results)