ld: Support input section description keyword: REVERSE

ld: Support input section description keyword: REVERSE

  PR 27565
  * ldlex.l: Add REVERSE.
  * ldgram.y: Allow REVERSE to be used wherever a sorting command can be used.
  * ld.h (struct wildcard_spec): Add 'reversed' field.
  * ldlang.h (lang_wild_statement_struct): Add 'filenames_reversed' field.
  * ldlang.c (compare_sections): Add reversed parameter. (wild_sort): Reverse the comparison if requested. (print_wild_statement): Handle the reversed field.
  * ld.texi: Document the new feature.
  * NEWS: Mention the new feature.
  * testsuite/ld-scripts/sort-file-reversed-1.d: New test driver.
  * testsuite/ld-scripts/sort-file-reversed-1.t: New test source.
  * testsuite/ld-scripts/sort-file-reversed-2.t: New test source.
  * testsuite/ld-scripts/sort-file-reversed-2.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-1.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-1.t: New test source.
  * testsuite/ld-scripts/sort-sections-reversed-2.t: New test source.
  * testsuite/ld-scripts/sort-sections-reversed-2.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-3.d: New test driver.
  * testsuite/ld-scripts/sort-sections-reversed-3.t: New test source.