Refactoring analysis downmix to use sig scaling #646

Job	Run time
CMake/Android/So/ARMv8/Release	13s
CMake MINGW	41s
CMake/Android/So/X86/Release	17s
CMake/Android/So/X64/Release	13s
Test build with CMake 3.16.0	1m 5s
CMake/Windows/Dll/X86/Release	1m 22s
CMake/Windows/Dll/X64/Release	1m 43s
CMake/Windows/Dll/ARMv8/Release	1m 13s
CMake/Linux/So/X64/Release	26s
CMake/MacOSX/So/X64/Release	34s
CMake/MacOSX/Framework/X64/Release	1m 20s
CMake/iOS/Dll/arm64/Release	35s
CMake/iOS/Framework/arm64/Release	39s
CMake/Windows/Lib/X86/Release	3m 10s
CMake/Windows/Lib/X64/Release	3m 20s
CMake/Windows/Lib/armv8/Release	2m 31s
CMake/Linux/Lib/X64/Release	1m 7s
CMake/MacOSX/Lib/X64/Release	1m 27s
CMake/iOS/Lib/arm64/Release	38s
CMake/Android/Lib/ARMv8/Release	13s
CMake/Android/Lib/X86/Release	17s
CMake/Android/Lib/X64/Release	20s
CMake/CustomModes/Linux/Lib/X64/Release	1m 8s
CMake/AssertionsFuzz/Windows/Lib/X64/Release	2m 27s
CMake/AssertionsFuzz/Linux/Lib/X64/Release	1m 1s
CMake/AssertionsFuzz/MacOSX/Lib/X64/Release	1m 18s
	29m 18s

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