[DWARFv5][DWARFLinker] Remove dsymutil-classic compatibility feature as it leads...

[DWARFv5][DWARFLinker] Remove dsymutil-classic compatibility feature as it leads to an error.

DWARFLinker has a compatibility feature with dsymutil-classic.
It may keep location expression attribute even if does not
reference live address. Current llvm-dwarfdump --verify
reports a error if variable references an address but is not
added into the .debug_names table.

error: Name Index @ 0x0: Entry for DIE @ 0xf35 (DW_TAG_variable) with name seed missing.

DW_TAG_variable
  DW_AT_name      ("seed")
  DW_AT_type      (0x00000000000047b7 "uint64_t")
  DW_AT_location  (DW_OP_addr 0x9ff8)  <<<< dead address

DWARFLinker does not add the variable into .debug_names table
because it references dead address. To have a valid variable and
consistent accelerator table it is necessary to remove location expression
referencing dead address. This patch removes dsymutil-classic
compatibilty feature.

Differential Revision: https://reviews.llvm.org/D153988