Revert "Add warning when (pre)loading paths with leading / (#4280 - #3106)"

Also closes: #6801

This reverts commit e59820ac94b7c9706298d5559608937dfca332e5.

(cherry picked from commit 11349a786be1fd02647493cfeff9883898ffd73e)

modules/gdscript/gd_functions.cpp

@@ -840,10 +840,6 @@ void GDFunctions::call(Function p_func,const Variant **p_args,int p_arg_count,Va
 				r_error.error=Variant::CallError::CALL_ERROR_INVALID_ARGUMENT;
 				r_error.argument=0;
 				r_ret=Variant();
-			} else if(((String)(*p_args[0])).begins_with("/")) {
-				r_error.error=Variant::CallError::CALL_ERROR_INVALID_ARGUMENT;
-				r_error.argument=0;
-				r_ret=RTR("Paths cannot start with '/', absolute paths must start with 'res://', 'user://', or 'local://'");
 			} else {
 				r_ret=ResourceLoader::load(*p_args[0]);
 			}

modules/gdscript/gd_parser.cpp

@@ -303,10 +303,6 @@ GDParser::Node* GDParser::_parse_expression(Node *p_parent,bool p_static,bool p_
 				_set_error("expected string constant as 'preload' argument.");
 				return NULL;
 			}
-			if (path.begins_with("/")) {
-				_set_error("Paths cannot start with '/', absolute paths must start with \'res://\', \'user://\', or \'local://\'");
-				return NULL;
-			}
 			if (!path.is_abs_path() && base_path!="")
 				path=base_path+"/"+path;
 			path = path.replace("///","//").simplify_path();
@@ -2026,10 +2022,6 @@ void GDParser::_parse_extends(ClassNode *p_class) {
 			_set_error("'extends' constant must be a string.");
 			return;
 		}
-		if (((String)(constant)).begins_with("/")) {
-			_set_error("Paths cannot start with '/', absolute paths must start with \'res://\', \'user://\', or \'local://\'");
-			return;
-		}
 
 		p_class->extends_file=constant;
 		tokenizer->advance();