Remove GCC ifunc #787

Job	Run time
linux_gcc_sanitizers	1m 35s
linux_gcc_mpopcnt (ubuntu-latest, Debug)	52s
linux_gcc (ubuntu-latest, Debug)	1m 7s
linux_gcc_mpopcnt (ubuntu-latest, Release)	50s
linux_gcc (ubuntu-latest, Release)	49s
windows_mingw64 (windows-latest, Debug)	3m 15s
windows_msvc2022	1m 44s
windows_msvc2022_POPCNT	1m 43s
windows_mingw64 (windows-latest, Release)	2m 57s
linux_128bit	1m 1s
linux_clang (ubuntu-latest, Debug)	2m 12s
linux_clang_mpopcnt (ubuntu-latest, Debug)	2m 58s
linux_clang (ubuntu-latest, Release)	2m 16s
linux_clang_mpopcnt (ubuntu-latest, Release)	2m 13s
linux_gcc_valgrind	1m 12s
macos_clang (macos-latest, Debug)	2m 41s
macos_clang (macos-latest, Release)	2m 21s
	31m 46s

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