Fix warning about used variable in GolangFlyweightGenerator. #1184

Job	Run time
C++ Clang 9 (Ubuntu 20.04)	1m 42s
C++ GCC 6 (Ubuntu 20.04)	1m 46s
C++ Clang 10 (Ubuntu 20.04)	1m 43s
C++ GCC 7 (Ubuntu 20.04)	1m 42s
C++ Clang 11 (Ubuntu 20.04)	1m 40s
C++ GCC 8 (Ubuntu 20.04)	1m 42s
C++ Clang 12 (Ubuntu 20.04)	1m 44s
C++ GCC 9 (Ubuntu 20.04)	1m 43s
C++ GCC 10 (Ubuntu 20.04)	1m 36s
C++ GCC 11 (Ubuntu 24.04)	1m 40s
C# 8.0.x	2m 57s
C++ GCC 12 (Ubuntu 24.04)	1m 54s
Java 17 (ubuntu-24.04)	1m 54s
C++ GCC 13 (Ubuntu 24.04)	1m 53s
Java 17 (windows-latest)	4m 33s
C++ GCC 14 (Ubuntu 24.04)	1m 27s
C++ Clang 13 (Ubuntu 24.04)	1m 35s
Java 17 (macos-latest)	1m 45s
C++ Clang 14 (Ubuntu 24.04)	1m 46s
Java 21 (ubuntu-24.04)	1m 58s
C++ Clang 15 (Ubuntu 24.04)	1m 33s
C++ Xcode (macOS)	1m 3s
C++ MSVC (Windows) (windows-latest)	6m 1s
Java 21 (windows-latest)	3m 53s
C++ Clang 16 (Ubuntu 24.04)	1m 23s
Java 21 (macos-latest)	1m 28s
C++ Clang 17 (Ubuntu 24.04)	1m 29s
Golang 1.22.x	2m 1s
C++ Clang 18 (Ubuntu 24.04)	1m 34s
Rust stable	58s
Rust beta	1m 8s
Rust nightly	1m 5s
	1h 2m 16s

Provide feedback