[DynInst_API:] [dyninst/dyninst] 72bba1: Remove Symtab(MappedFile*) (#1598)

[Tim Haines <noreply@xxxxxxxxxx>]

  Branch: refs/heads/master
  Home:   https://github.com/dyninst/dyninst
  Commit: 72bba13ebfc312adc588212a223dbadbb91fe770
      https://github.com/dyninst/dyninst/commit/72bba13ebfc312adc588212a223dbadbb91fe770
  Author: Tim Haines <thaines.astro@xxxxxxxxx>
  Date:   2023-10-30 (Mon, 30 Oct 2023)

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

  Log Message:
  -----------
  Remove Symtab(MappedFile*) (#1598)

It's never used. MappedFile is also an opaque type here, so users
could never have used it. This makes it not an ABI/API-breaking change.