i#1729/i#1569 A64 traces: temporarily revert trace packing to fix A64
i#1729/i#1569 A64 traces: temporarily revert trace packing to fix A64

Temporarily removes the drcachesim trace_entry_t packing to get the A64
tests working until the A64 instrumentation is generalized to handle
unconstrained offsets.

Review-URL: https://codereview.appspot.com/307320043

AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio