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

This CL optimizes tracer instrumentation for saving type and size fields,
and instrumentation for saving pc fields on x86 architecture.
It has small performance improvement (~5%) by reducing the number of
instructions and memory writes.

Review-URL: https://codereview.appspot.com/244490043

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