Fix classpath used for Gradle Plugin integration tests in Eclipse

See gh-19841

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/testkit/GradleBuild.java

@@ -86,8 +86,9 @@ public class GradleBuild {
 	}
 
 	private List<File> pluginClasspath() {
-		return Arrays.asList(new File("bin"), new File("build/classes/java/main"), new File("build/resources/main"),
-				new File(pathOfJarContaining(LaunchScript.class)), new File(pathOfJarContaining(ClassVisitor.class)),
+		return Arrays.asList(new File("bin/main"), new File("build/classes/java/main"),
+				new File("build/resources/main"), new File(pathOfJarContaining(LaunchScript.class)),
+				new File(pathOfJarContaining(ClassVisitor.class)),
 				new File(pathOfJarContaining(DependencyManagementPlugin.class)),
 				new File(pathOfJarContaining(PropertiesKt.class)), new File(pathOfJarContaining(KotlinLogger.class)),
 				new File(pathOfJarContaining(KotlinPlugin.class)), new File(pathOfJarContaining(KotlinProject.class)),