[DynInst_API:] [dyninst/dyninst] 4f6f3d: Remove undefined behavior from Symtab::Type (#706)

[Tim Haines <noreply@xxxxxxxxxx>]

  Branch: refs/heads/master
  Home:   https://github.com/dyninst/dyninst
  Commit: 4f6f3dbb59312fb4edc75f618d76cd253460d714
      https://github.com/dyninst/dyninst/commit/4f6f3dbb59312fb4edc75f618d76cd253460d714
  Author: Tim Haines <thaines.astro@xxxxxxxxx>
  Date:   2020-03-10 (Tue, 10 Mar 2020)

  Changed paths:
    M symtabAPI/h/Type.h
    M symtabAPI/src/Type.C

  Log Message:
  -----------
  Remove undefined behavior from Symtab::Type (#706)

Calling a member function of a base class before the base class's constructor has completed is undefined behavior.