Polish "Handle root output directory when extracting layers"

See gh-50501

Author: mhalbritter

spring-boot-project/spring-boot-tools/spring-boot-jarmode-tools/src/main/java/org/springframework/boot/jarmode/tools/ExtractCommand.java

@@ -373,8 +373,8 @@ private static File assertFileIsContainedInDirectory(File directory, File file,
 		return file;
 	}
 
-	private static boolean isFileContainedInDirectory(Path canonicalOutputPath, Path canonicalFilePath) {
-		return !canonicalFilePath.equals(canonicalOutputPath) && canonicalFilePath.startsWith(canonicalOutputPath);
+	private static boolean isFileContainedInDirectory(Path directory, Path file) {
+		return !file.equals(directory) && file.startsWith(directory);
 	}
 
 	@FunctionalInterface