[Mono] Disable LLVM JIT (#2134)

Author: fanyang-mono

src/BenchmarkDotNet/Extensions/ProcessExtensions.cs

@@ -149,15 +149,6 @@ internal static void SetEnvironmentVariables(this ProcessStartInfo start, Benchm
             // disable ReSharper's Dynamic Program Analysis (see https://github.com/dotnet/BenchmarkDotNet/issues/1871 for details)
             start.EnvironmentVariables["JETBRAINS_DPA_AGENT_ENABLE"] = "0";
 
-            if (benchmarkCase.Job.Infrastructure.Toolchain is MonoAotLLVMToolChain)
-            {
-                MonoAotLLVMRuntime aotruntime = (MonoAotLLVMRuntime)benchmarkCase.GetRuntime();
-
-                if (aotruntime.AOTCompilerMode == MonoAotCompilerMode.llvm)
-                {
-                    start.EnvironmentVariables["MONO_ENV_OPTIONS"] = "--llvm";
-                }
-            }
 
             if (!benchmarkCase.Job.HasValue(EnvironmentMode.EnvironmentVariablesCharacteristic))
                 return;