Update drcachesim and sample tracers to record original, not emulation, instruction sequences

With #3112 (closed) we have support for marking emulation sequences where the original application code is distinct from what is executed on the machine. In addition to emulation for features from different generations of architectures, we plan to have emulation markers for rep string expansion and scatter-gather expansion. This issue covers changing the drcachesim/drmemtrace tracer and all our sample tracers to record the original, rather than emulation, sequences. We already have hardcoded special cases for rep string expansion in drcachesim; we should be able to eliminate that and replace with general handling.