Don't detect main method from launcher classes

Update `MainMethod` discovery so that launcher classes from the
`org.springframework.boot.loader` code are not considered. This restores
the behavior of Spring Boot 2.7.11 and allows remote restart of uber
jars without pulling the loader classes into the `RestartClassLoader`.

Fixes gh-39733

spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/MainMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,7 +43,7 @@ class MainMethod {
 		StackTraceElement[] stackTrace = thread.getStackTrace();
 		for (int i = stackTrace.length - 1; i >= 0; i--) {
 			StackTraceElement element = stackTrace[i];
-			if ("main".equals(element.getMethodName())) {
+			if ("main".equals(element.getMethodName()) && !isLoaderClass(element.getClassName())) {
 				Method method = getMainMethod(element);
 				if (method != null) {
 					return method;
@@ -53,6 +53,10 @@ class MainMethod {
 		throw new IllegalStateException("Unable to find main method");
 	}
 
+	private boolean isLoaderClass(String className) {
+		return className.startsWith("org.springframework.boot.loader.");
+	}
+
 	private Method getMainMethod(StackTraceElement element) {
 		try {
 			Class<?> elementClass = Class.forName(element.getClassName());