Fix #12063 convert PHP single-quote to C double-quote string

Author: remicollet

build/gen_stub.php

@@ -1768,6 +1768,10 @@ public function getCExpr(): ?string
         // $this->expr has all its PHP constants replaced by C constants
         $prettyPrinter = new Standard;
         $expr = $prettyPrinter->prettyPrintExpr($this->expr);
+        // PHP single-quote to C double-quote string
+        if ($this->type->isString()) {
+            $expr = preg_replace("/(^'|'$)/", '"', $expr);
+        }
         return $expr[0] == '"' ? $expr : preg_replace('(\bnull\b)', 'NULL', str_replace('\\', '', $expr));
     }
 }

ext/zend_test/test.stub.php

@@ -143,7 +143,7 @@ enum ZendTestUnitEnum {
 
     enum ZendTestStringEnum: string {
         case Foo = "Test1";
-        case Bar = "Test2";
+        case Bar = 'Test2';
         case Baz = "Test2\\a";
         case FortyTwo = "42";
     }