Wrap class const LHS in parens if necessary

This looks like a very old bug in the pretty printer that showed
up in PHP 8 tests.

Author: nikic

lib/PhpParser/PrettyPrinter/Standard.php

@@ -577,7 +577,7 @@ protected function pExpr_ConstFetch(Expr\ConstFetch $node) {
     }
 
     protected function pExpr_ClassConstFetch(Expr\ClassConstFetch $node) {
-        return $this->p($node->class) . '::' . $this->p($node->name);
+        return $this->pDereferenceLhs($node->class) . '::' . $this->p($node->name);
     }
 
     protected function pExpr_PropertyFetch(Expr\PropertyFetch $node) {

lib/PhpParser/PrettyPrinterAbstract.php

@@ -1157,6 +1157,9 @@ protected function initializeFixupMap() {
                 'var' => self::FIXUP_DEREF_LHS,
                 'name' => self::FIXUP_BRACED_NAME,
             ],
+            Expr\ClassConstFetch::class => [
+                'var' => self::FIXUP_DEREF_LHS,
+            ],
             Scalar\Encapsed::class => [
                 'parts' => self::FIXUP_ENCAPSED,
             ],

test/code/prettyPrinter/expr/uvs.test

@@ -10,6 +10,7 @@ $A::{$b[$c]}();
 A::$$b[$c]();
 ($a->b)();
 (A::$b)();
+('a' . 'b')::X;
 -----
 !!php7
 (function () {
@@ -21,3 +22,4 @@ $A::{$b[$c]}();
 A::${$b}[$c]();
 ($a->b)();
 (A::$b)();
+('a' . 'b')::X;