in release builds, use it to fine-tune physical file comparisons in
ma_test_recovery.pl.


storage/maria/CMakeLists.txt:
  build maria_dump_log under Windows too
storage/maria/maria_chk.c:
  make --zerofill-keep-lsn usable in release builds too, it makes sense.
  This option needn't reset state's LSNs, and it's more useful if it
  does not (see added comment) as it changes less the table.
storage/maria/unittest/ma_test_recovery.pl:
  - getting rid of 'cmp'
  - if physical comparison of two MAD or MAI files fails, it might
  be in irrelevant portions (unushed index or data page pieces):
  we use --zerofill-keep-lsn and retry the comparison. This fixes
  a part of test failures under Windows.