[DynInst_API:] [dyninst/dyninst] 8871ef: Fix unnecessary multiple calls to buildSysRegMap.

[Sasha NÃcolas <noreply@xxxxxxxxxx>]

  Branch: refs/heads/ARMv8
  Home:   https://github.com/dyninst/dyninst
  Commit: 8871efe5daa1dec718ed86ced6b62e4fc8c236c1
      https://github.com/dyninst/dyninst/commit/8871efe5daa1dec718ed86ced6b62e4fc8c236c1
  Author: Sasha @leela <sasha@xxxxxxxxxxx>
  Date:   2019-02-14 (Thu, 14 Feb 2019)

  Changed paths:
    M instructionAPI/src/InstructionDecoder-aarch64.h
    M instructionAPI/src/aarch64_opcode_tables.C

  Log Message:
  -----------
  Fix unnecessary multiple calls to buildSysRegMap.

This function should be called only once, but was being called for every
instruction to be decoded. As a result, dyninst would take a long time
to execute. Now to simply run test1_1 on create mode takes 28 seconds,
as opposed to 58 before this fix, and now closer to 20 seconds for x86_64.