message: refactor: Simplify loop with DWARFCompileUnit::Extract
  Forgotten small simplification in D40212.
diff: @@ -97,12 +97,8 @@ void DWARFDebugInfo::ParseCompileUnitHeadersIfNeeded() {
  if (m_compile_units.empty()) {
  if (m_dwarf2Data != NULL) {
  lldb::offset_t offset = 0;
  - for (;;) {
  - DWARFCompileUnitSP cu_sp =
  - DWARFCompileUnit::Extract(m_dwarf2Data, &offset);
  - if (cu_sp.get() == NULL)
  - break;
  -
  + DWARFCompileUnitSP cu_sp;
  + while ((cu_sp = DWARFCompileUnit::Extract(m_dwarf2Data, &offset))) {
  m_compile_units.push_back(cu_sp);
  offset = cu_sp->GetNextCompileUnitOffset();
  