Use @AfterEach to close the source jar file

Update `JarFileWrapperTests` so that the jar files are closed after each
test.

See gh-22991

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileWrapperTests.java

@@ -30,6 +30,7 @@ import java.util.jar.JarOutputStream;
 import java.util.jar.Manifest;
 import java.util.zip.ZipEntry;
 
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
@@ -51,11 +52,16 @@ class JarFileWrapperTests {
 	private JarFileWrapper wrapper;
 
 	@BeforeEach
-	void setup(@TempDir File temp) throws IOException {
+	void setup(@TempDir File temp) throws Exception {
 		this.parent = new SpyJarFile(createTempJar(temp));
 		this.wrapper = new JarFileWrapper(this.parent);
 	}
 
+	@AfterEach
+	void cleanup() throws Exception {
+		this.parent.close();
+	}
+
 	private File createTempJar(File temp) throws IOException {
 		File file = new File(temp, "temp.jar");
 		new JarOutputStream(new FileOutputStream(file)).close();