Fix test assertions per code review feedback

- Replace assertEmpty() with assertNoErrors() for clearer test intent
- Replace assert() with assertInstanceOf() for proper PHPUnit assertions

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: janedbal

tests/PHPStan/Analyser/AnalyserTest.php

@@ -119,20 +119,20 @@ public function testFileWithAnIgnoredErrorMessages(): void
 	public function testFileWithAnIgnoredErrorIdentifiers(): void
 	{
 		$result = $this->runAnalyser([['identifiers' => ['tests.alwaysFail']]], true, __DIR__ . '/data/bootstrap-error.php', false);
-		$this->assertEmpty($result);
+		$this->assertNoErrors($result);
 	}
 
 	public function testFileWithAnIgnoredErrorIdentifiersWithPath(): void
 	{
 		$result = $this->runAnalyser([['identifiers' => ['tests.alwaysFail'], 'path' => __DIR__ . '/data/bootstrap-error.php']], true, __DIR__ . '/data/bootstrap-error.php', false);
-		$this->assertEmpty($result);
+		$this->assertNoErrors($result);
 	}
 
 	public function testFileWithAnIgnoredErrorIdentifiersWithWrongIdentifier(): void
 	{
 		$result = $this->runAnalyser([['identifiers' => ['wrong.identifier']]], true, __DIR__ . '/data/bootstrap-error.php', false);
 		$this->assertCount(2, $result);
-		assert($result[0] instanceof Error);
+		$this->assertInstanceOf(Error::class, $result[0]);
 		$this->assertSame('Fail.', $result[0]->getMessage());
 		assert(is_string($result[1]));
 		$this->assertSame('Ignored error pattern wrong.identifier was not matched in reported errors.', $result[1]);