i#1703 cache simulator: optimize tracer
i#1703 cache simulator: optimize tracer

Applies the (forthcoming) memtrace_opt optimizations (fewer spills, fewer
writes to the pipe) to the tracer to improve performance.

Review-URL: https://codereview.appspot.com/243410043

AmesianX/dynamorio,bl4ckic3/dynamorio,daksunt/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,daksunt/dynamorio,daksunt/dynamorio,daksunt/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,code4bones/dynamorio,daksunt/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio