tests: ztest/base: fix incorrect userspace filtering

The filter here should be used to filter for capability:
whether the platform configuration supports userspace. And if
it does support userspace, we then enable CONFIG_TEST_USERSPACE
(and thus CONFIG_USERSPACE) for testing. We should not be
filtering for whether userspace is enabled, but should really
be filtering for whether userspace is supported.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

tests/ztest/base/testcase.yaml

@@ -16,7 +16,7 @@ tests:
     integration_platforms:
       - native_sim
   testing.ztest.base.verbose_0_userspace:
-    filter: CONFIG_USERSPACE
+    filter: CONFIG_ARCH_HAS_USERSPACE
     extra_args: CONF_FILE=prj_verbose_0.conf
     tags:
       - userspace