ast:remove cached_name, as auto_str_methods free it

vlib/v/ast/ast.v

@@ -1094,7 +1094,6 @@ pub mut:
 	mod            string
 	name           string
 	full_name      string
-	cached_name    string
 	kind           IdentKind
 	info           IdentInfo
 	is_mut         bool // if mut *token* is before name. Use `is_mut()` to lookup mut variable

vlib/v/ast/str.v

@@ -525,13 +525,7 @@ pub fn (x &Expr) str() string {
 			return 'spawn ${x.call_expr}'
 		}
 		Ident {
-			if x.cached_name != '' {
-				return x.cached_name
-			}
-			unsafe {
-				x.cached_name = util.strip_main_name(x.name.clone())
-			}
-			return x.cached_name
+			return x.name.clone()
 		}
 		IfExpr {
 			mut parts := []string{}