Added config option for AVX2 dataset init

-1 = Auto detect
0 = Always disabled
1 = Enabled if AVX2 is supported

src/crypto/randomx/randomx.cpp

@@ -381,7 +381,7 @@ extern "C" {
 					break;
 
 				case RANDOMX_FLAG_JIT:
-					cache->jit          = new randomx::JitCompiler(false);
+					cache->jit          = new randomx::JitCompiler(false, true);
 					cache->initialize   = &randomx::initCacheCompile;
 					cache->datasetInit  = nullptr;
 					cache->memory       = memory;