[Java] Upgrade to Checkstyle 10.21.0. #4

Job	Run time
C++ Xcode (macOS)	1m 30s
C++ GCC 6 (Ubuntu 20.04)	1m 38s
C++ Clang 9 (Ubuntu 20.04)	2m 1s
C++ GCC 7 (Ubuntu 20.04)	1m 36s
C++ Clang 13 (Ubuntu 24.04)	1m 35s
C++ Clang 10 (Ubuntu 20.04)	2m 18s
C++ GCC 8 (Ubuntu 20.04)	1m 42s
C++ GCC 11 (Ubuntu 24.04)	1m 50s
C++ Clang 14 (Ubuntu 24.04)	1m 39s
C++ Clang 11 (Ubuntu 20.04)	1m 56s
C++ GCC 9 (Ubuntu 20.04)	2m 11s
C++ GCC 12 (Ubuntu 24.04)	1m 41s
C++ Clang 15 (Ubuntu 24.04)	1m 38s
C++ Clang 12 (Ubuntu 20.04)	2m 9s
C++ GCC 10 (Ubuntu 20.04)	1m 36s
C++ GCC 13 (Ubuntu 24.04)	1m 43s
C++ Clang 16 (Ubuntu 24.04)	1m 36s
C++ GCC 14 (Ubuntu 24.04)	1m 19s
C++ Clang 17 (Ubuntu 24.04)	1m 40s
C++ MSVC (Windows) (windows-latest)	5m 4s
C# 8.0.x	2m 44s
Golang 1.22.x	1m 40s
C++ Clang 18 (Ubuntu 24.04)	1m 44s
Java 17 (ubuntu-24.04)	1m 39s
Java 17 (windows-latest)	3m 34s
Rust stable	51s
Java 17 (macos-latest)	1m 32s
Rust beta	53s
Java 21 (ubuntu-24.04)	1m 45s
Rust nightly	55s
Java 21 (windows-latest)	3m 49s
Java 21 (macos-latest)	1m 22s
	1h 0m 50s

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