Remove unnecessary code path in custom catch main

Author: franzpoeschel

test/CatchRunner.cpp

@@ -42,12 +42,6 @@ int main(int argc, char *argv[])
 #else
 int main(int argc, char *argv[])
 {
-    Catch::Session session;
-    int result = session.applyCommandLine(argc, argv);
-    if (result == 0)
-    {
-        result = session.run();
-    }
-    return result;
+    throw std::runtime_error("Serial tests use Catch2's provided main.");
 }
 #endif