Harden variant decoding

### Describe the enhancement requested

org.apache.parquet.variant.Variant is brittle against malformed variants, whereas the arrow variant is very strict and includes an optional deep validate phase

* Harden the java implementation, where it doesn't impose any performance penalty
* add tests which can also generate malformed files to add to the parquet test files

The work in #3481 should include some of this or this should be an immediate followon (preferred)

### Component(s)

parquet-variant

首先阅读 org.apache.parquet.variant.Variant 和 parquet-variant 组件，然后将其对格式错误输入的处理与 Arrow variant 进行比较，并审查 #3481 中的工作。完成的标准是：在不产生不必要性能成本的情况下增强 Java variant 解码的健壮性，并添加能够生成格式错误文件且将其加入 Parquet 测试文件的测试。

由索引模型根据 Issue 内容生成。