[BUGFIX] Fixing pybind11::error_already_set.matches to also work with exception subclasses (#1715)

* Fixing order of arguments in call to PyErr_GivenExceptionMatches in pybind11::error_already_set.matches

* Added tests on error_already_set::matches fix for exception base classes
diff --git a/tests/test_exceptions.py b/tests/test_exceptions.py
index 8d37c09..6edff9f 100644
--- a/tests/test_exceptions.py
+++ b/tests/test_exceptions.py
@@ -48,7 +48,9 @@
 
 
 def test_exception_matches():
-    m.exception_matches()
+    assert m.exception_matches()
+    assert m.exception_matches_base()
+    assert m.modulenotfound_exception_matches_base()
 
 
 def test_custom(msg):