Multiple tests can have same name as long as their tags differ

This change also changes it so that test case macros using a
class name can have same name **and** tags as long as the
used class name differs.

Closes #1915
Closes #1999

tests/ExtraTests/X31-DuplicatedTestCases.cpp

@@ -0,0 +1,16 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+/**\file
+ * Checks that test cases with identical name and tags are reported as error
+ */
+
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("A test case with duplicated name and tags", "[tag1][tag2]") {}
+TEST_CASE("A test case with duplicated name and tags", "[tag1][tag2]") {}