Add mallocTrim command to vmTool

[kkHAIKE]

malloc_trim 是排查 java 64M 问题的重要函数，参考 https://juejin.cn/post/6854573220733911048

CLOSE: #3020

[CLAassistant]

All committers have signed the CLA.

[hengyunabc]

缺少测试，需要增加基本的能调用成功的测试。不一定要构造出对应的场景。比如在 linux 下跑测试时要调用成功。

[kkHAIKE]

根据 malloc_trim 的官方文档 https://man7.org/linux/man-pages/man3/malloc_trim.3.html
-> 有内存释放才会返回 true

而且 trim_native_heap 的实现 https://github.com/openjdk/jdk21/blob/jdk-21%2B35/src/hotspot/os/linux/os_linux.cpp#L5518
-> 只要是 glibc 就会返回 true

所以如果要补充单元测试的话,可能只有直接调用,并不能检测结果是否 true.

@Test
public void testMallocTrim() {
    VmTool vmtool = initVmTool();
    vmtool.mallocTrim();
}

另外: 非 glibc 的 mallocTrim 返回 false 是否更合适

[hengyunabc]

看起来，好像是 mallocTrim 函数要返回两个信息： 是否有支持，是否有成功。
考虑增加一个 isMallocTrimSupported 的函数？

[kkHAIKE]

可以把返回改为 int，然后 command 层去适配输出。。

主要我是觉得单元测试不好写，只能是像上个回复一样简单的调用，还有必要写吗

[hengyunabc]

可以把返回改为 int，然后 command 层去适配输出。。

主要我是觉得单元测试不好写，只能是像上个回复一样简单的调用，还有必要写吗

单元测试的作用主要是确保编译为 so 之后，在java层能正常调用。功能是否正常可以先不管。

另外需要同步更新下 wiki 文档。

[Copilot]

Pull Request Overview

This PR adds two new commands, mallocTrim and mallocStats, to vmTool to help diagnose Java memory issues as described in the linked issue and reference article.

• Updated English and Chinese documentation with usage examples.
• Extended VmToolCommand, VmToolMXBean, and VmTool classes to support new actions.
• Added native JNI implementations and test cases for the new commands.

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
site/docs/en/doc/vmtool.md	Added commands and usage examples for mallocTrim and mallocStats in English.
site/docs/doc/vmtool.md	Added commands and usage examples for mallocTrim and mallocStats in Chinese.
core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java	Updated command help text, enum, and process() method to include new actions.
arthas-vmtool/src/test/java/arthas/VmToolTest.java	Added basic tests for mallocTrim and mallocStats.
arthas-vmtool/src/main/native/src/jni-library.cpp	Added JNI implementations for mallocTrim and mallocStats.
arthas-vmtool/src/main/java/arthas/VmToolMXBean.java	Updated interface to include mallocTrim and mallocStats methods.
arthas-vmtool/src/main/java/arthas/VmTool.java	Provided native method wrappers for mallocTrim and mallocStats.

Comments suppressed due to low confidence (2)

arthas-vmtool/src/test/java/arthas/VmToolTest.java:215

• Consider adding assertions to validate the result of mallocTrim instead of just executing the method.

public void testMallocTrim() {

arthas-vmtool/src/test/java/arthas/VmToolTest.java:221

• Consider adding assertions or validations to ensure mallocStats returns the expected outcome.

public void testMallocStats() {