tests: valgrind: generate suppressions list for new tests-suppress-new-valgrind-errors-in-python

That will help with updating suppresions lists in future

tests/meson.build

@@ -248,6 +248,7 @@ if valgrind.found()
         '--track-origins=yes',
         '--show-leak-kinds=definite,possible',
         '--show-error-list=yes',
+        '--gen-suppressions=all',
         '--suppressions=' + libfprint_suppressions,
         '--suppressions=' + glib_suppressions,
         '--suppressions=' + python_suppressions,