change BoosterSpeedFactor to simple multiplier #1084

Job	Run time
g2.dat	18s
Lint Commit Message	0s
Check code formatting	1m 21s
Check changelog formatting	12s
Ubuntu Linux (jammy, debug, [http, network, flac, vorbis OpenGL] disabled) using clang	11m 27s
Ubuntu Linux (debug) using clang, coverage enabled	6m 57s
Ubuntu Linux (AppImage, x86_64)	3m 36s
Android	5m 57s
Ubuntu Linux (Docker)	0s
Ubuntu Linux (jammy, x86_64, portable)	4m 44s
macOS (x64) using CMake	7m 23s
Debian Linux (bullseye, x86_64, portable)	4m 23s
Windows (win32)	9m 50s
macOS (arm64) using CMake	5m 3s
Ubuntu Linux (jammy, i686, portable)	5m 30s
Windows (win32) using mingw	3m 44s
Windows (x64)	10m 0s
Windows (arm64)	10m 26s
macOS universal app bundle	41s
	1h 31m 32s

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