Tell Acton to target native platform

By default, Acton optimizes for portability, so on Linux, the output
binary targets GNU libc 2.27, which is rather old (~Ubuntu 18.04). It
also only uses base features of the x86_64 CPU, so features like AVX512
or similar would not be used. By setting --target native, the output
executable is instead optimized for the machine we are running on and
can typically run much faster, sometimes up to 2x faster.

Author: plajjan

bench/bench_acton.yaml

@@ -24,7 +24,7 @@ environments:
     compiler: actonc
     compiler_version_command: actonc --version
     version: latest
-    build: actonc app.act
+    build: actonc --target native app.act
     after_build:
       - mv app out
     out_dir: out