Remove DSTACK support (#6346)

Debugstacks is not useful, we don't really use it, the DebugStack is not pertinent, gdb and lldb are better if we really want to debug.

src/unittest/test.cpp

@@ -228,8 +228,6 @@ void TestGameDef::defineSomeNodes()
 
 bool run_tests()
 {
-	DSTACK(FUNCTION_NAME);
-
 	u64 t1 = porting::getTimeMs();
 	TestGameDef gamedef;