[1.9.x] Revert "Fixed #25417 -- Added a field check for invalid default values."

This reverts commit 71ebcb85b9.

Backport of 976bd519a8 from master

django/db/models/fields/__init__.py

@@ -203,7 +203,6 @@ class Field(RegisterLookupMixin):
         errors = []
         errors.extend(self._check_field_name())
         errors.extend(self._check_choices())
-        errors.extend(self._check_default())
         errors.extend(self._check_db_index())
         errors.extend(self._check_null_allowed_for_primary_keys())
         errors.extend(self._check_backend_specific_checks(**kwargs))
@@ -280,22 +279,6 @@ class Field(RegisterLookupMixin):
         else:
             return []
 
-    def _check_default(self):
-        if self.has_default():
-            default = self.get_default()
-            try:
-                self.clean(default, None)
-            except exceptions.ValidationError as messages:
-                return [
-                    checks.Error(
-                        "Invalid 'default' value: %s" % message,
-                        hint=None,
-                        obj=self,
-                        id='fields.E008',
-                    ) for message in messages
-                ]
-        return []
-
     def _check_db_index(self):
         if self.db_index not in (None, True, False):
             return [