configure.ac: cast utest to __m128i_u* in avx2 check for _mm_loadu_si128 #613

Job	Run time
CMake MINGW	2m 25s
Test build with CMake 3.16.0	1m 0s
CMake/Android/So/ARMv8/Release	1m 11s
CMake/Android/So/X86/Release	1m 48s
CMake/Android/So/X64/Release	1m 1s
CMake/Windows/Dll/X86/Release	1m 30s
CMake/Windows/Dll/X64/Release	2m 38s
CMake/Windows/Dll/ARMv8/Release	3m 0s
CMake/Linux/So/X64/Release	31s
CMake/MacOSX/So/X64/Release	39s
CMake/MacOSX/Framework/X64/Release	1m 24s
CMake/iOS/Dll/arm64/Release	33s
CMake/iOS/Framework/arm64/Release	34s
CMake/Windows/Lib/X86/Release	2m 12s
CMake/Windows/Lib/X64/Release	2m 55s
CMake/Windows/Lib/armv8/Release	1m 36s
CMake/Linux/Lib/X64/Release	1m 49s
CMake/MacOSX/Lib/X64/Release	1m 18s
CMake/iOS/Lib/arm64/Release	39s
CMake/Android/Lib/ARMv8/Release	1m 9s
CMake/Android/Lib/X86/Release	1m 45s
CMake/Android/Lib/X64/Release	1m 20s
CMake/CustomModes/Linux/Lib/X64/Release	1m 45s
CMake/AssertionsFuzz/Windows/Lib/X64/Release	2m 43s
CMake/AssertionsFuzz/Linux/Lib/X64/Release	2m 10s
CMake/AssertionsFuzz/MacOSX/Lib/X64/Release	1m 24s
	40m 59s

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