Replace handling of AstroidError with MroError

I'm not sure why AstroidError was added in the first place, as this is
the most general exception in astroid.

astroid/brain/brain_builtin_inference.py

@@ -13,7 +13,7 @@ from textwrap import dedent
 import six
 from astroid import (MANAGER, UseInferenceDefault, AttributeInferenceError,
                      inference_tip, InferenceError, NameInferenceError,
-                     AstroidTypeError, AstroidError)
+                     AstroidTypeError, MroError)
 from astroid import arguments
 from astroid.builder import AstroidBuilder
 from astroid import helpers
@@ -548,8 +548,8 @@ def infer_isinstance(callnode, context=None):
             obj_node, class_container, context)
     except AstroidTypeError as exc:
         raise UseInferenceDefault("TypeError: " + str(exc))
-    except AstroidError:
-        raise UseInferenceDefault
+    except MroError as exc:
+        raise UseInferenceDefault from exc
     if isinstance_bool is util.Uninferable:
         raise UseInferenceDefault
     return nodes.Const(isinstance_bool)

astroid/helpers.py

@@ -91,8 +91,6 @@ def object_isinstance(node, class_or_seq, context=None):
     :rtype: bool
     :raises AstroidTypeError: if the given ``classes_or_seq`` are not types
-    :raises AstroidError: if the type of the given node cannot be inferred
-        or its type's mro doesn't work
     """
     if not isinstance(class_or_seq, (tuple, list)):
         class_seq = (class_or_seq,)