The code in SymbolTable::allocate_symbols has some strange conditionals:

  if (DumpSharedSpaces) {
    // TODO: Special handling of Symbol allocation for DumpSharedSpaces will be removed
    // in JDK-8250989
    c_heap = false;
  }
  if (c_heap) {
  } else if (DumpSharedSpaces) {
  } else {
  }

Body of conditionals removed when irrelevant. This could be cleaned up by doing the symbol allocation in the first DumpSharedSpaces-branch and removing the second one and returning early.