Add tests for $this->i ?? -1 inside both MyClass and MyClassUninitialized

Addresses review feedback: tests verify that $this->prop access inside
the class does not produce false positive warnings for either initialized
or uninitialized typed properties.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php

@@ -375,7 +375,7 @@ public function testBug14393(): void
 		$this->analyse([__DIR__ . '/data/bug-14393.php'], [
 			[
 				'Property Bug14393\MyClass::$i (int) on left side of ?? is not nullable.',
-				17,
+				27,
 			],
 		]);
 	}

tests/PHPStan/Rules/Variables/data/bug-14393.php

@@ -5,11 +5,21 @@
 class MyClass
 {
 	public int $i = 10;
+
+	public function doFoo(): void
+	{
+		var_dump($this->i ?? -1);
+	}
 }
 
 class MyClassUninitialized
 {
 	public int $i;
+
+	public function doFoo(): void
+	{
+		var_dump($this->i ?? -1);
+	}
 }
 
 $o = new MyClass();