[tedd4u]

Thanks for getting to the bottom of this.

Looks like -Oz bumps validate up another few percent.

  % c++ -Oz -DSIMDJSON_IMPLEMENTATION_ARM64=1 -o benchmark benchmark.cpp simdjson.cpp -std=c++11
  % ./benchmark
  minify : 6.73381 GB/s
  validate: 17.8548 GB/s