[DynInst_API:] [dyninst/dyninst] 042a3d: Protect against self-assignment in copy constructors

[Tim Haines <noreply@xxxxxxxxxx>]

  Branch: refs/heads/fix_self_assign
  Home:   https://github.com/dyninst/dyninst
  Commit: 042a3d2b12a75e1fd4354bc18223626396842993
      https://github.com/dyninst/dyninst/commit/042a3d2b12a75e1fd4354bc18223626396842993
  Author: Tim Haines <thaines.astro@xxxxxxxxx>
  Date:   2023-05-09 (Tue, 09 May 2023)

  Changed paths:
    M common/src/Edge.C
    M common/src/Node.C

  Log Message:
  -----------
  Protect against self-assignment in copy constructors

These were found by cppcheck:

common/src/Node.C:198:29: warning: 'operator=' should check for assignment to self to avoid problems with dynamic memory. [operatorEqToSelf]
NodeIterator &NodeIterator::operator=(const NodeIterator &rhs) {
                            ^
common/src/Edge.C:108:29: warning: 'operator=' should check for assignment to self to avoid problems with dynamic memory. [operatorEqToSelf]
EdgeIterator &EdgeIterator::operator=(const EdgeIterator &rhs) {