Add test for arrow function in global scope

Author: sirbrillig

Tests/VariableAnalysisSniff/ArrowFunctionTest.php

@@ -58,6 +58,7 @@ public function testArrowFunctionsWithoutUnusedBeforeUsed()
 			102,
 			112,
 			150,
+			184,
 		];
 		$this->assertSame($expectedWarnings, $lines);
 	}

Tests/VariableAnalysisSniff/fixtures/ArrowFunctionFixture.php

@@ -175,3 +175,14 @@ function arrowFunctionWithNestedArrowFunction() {
 	];
 	$fn();
 }
+
+// Arrow function in global scope
+array_map(
+	fn(
+		$dir,
+		string $bar,
+		\My\Class|bool $foo, // Unused variable $foo
+		\My\Class|bool $baz,
+	) => PREFIX_DIR . $dir . $bar . $baz,
+	PHP_ERROR_LOGS['ignore_dirs']
+);