Cleanup for performance reasons

* Eliminated some copies
* Made makeTestCase fit into 4 arguments -- avoids spills on Win64
* Made string literals into StringRef literals

projects/SelfTest/IntrospectiveTests/CmdLine.tests.cpp

@@ -15,7 +15,7 @@
 #   pragma clang diagnostic ignored "-Wc++98-compat"
 #endif
 
-inline Catch::TestCase fakeTestCase( const char* name, const char* desc = "" ){ return Catch::makeTestCase( nullptr, "", name, desc, CATCH_INTERNAL_LINEINFO ); }
+inline Catch::TestCase fakeTestCase(const char* name, const char* desc = "") { return Catch::makeTestCase(nullptr, "", { name, desc }, CATCH_INTERNAL_LINEINFO); }
 
 TEST_CASE( "Parse test names and tags" ) {