Rocksdb - failing tests

These tests fail on buildbot regularly :
Debug Win64:

• rocksdb.autoinc_vars_thread
  e.g http://buildbot.askmonty.org/buildbot/builders/winx64-debug/builds/3346/steps/test/logs/stdio

• rocksdb.validate_datadic
  e.g http://buildbot.askmonty.org/buildbot/builders/winx64-debug/builds/3346/steps/test/logs/stdio

• rocksdb.unique_check
  e.g http://buildbot.askmonty.org/buildbot/builders/winx64-debug/builds/3342/steps/test/logs/stdio

Optmized Win64 :

• rocksdb.bloomfilter
  e.g http://buildbot.askmonty.org/buildbot/builders/winx64-packages/builds/2954/steps/test/logs/stdio

Xenial fulltest:

• rocksdb_sys_vars.rocksdb_flush_memtable_on_analyze_basic
• rocksdb.col_opt_not_null
• rocksdb.col_opt_null
• rocksdb.col_opt_unsigned
• rocksdb.col_opt_zerofill
• rocksdb.type_float
  e.g. http://buildbot.askmonty.org/buildbot/builders/kvm-fulltest/builds/8335/steps/test_3/logs/stdio

Developers reported that validate_datadic and autoinc_vars_thread also occasionally fail on Linux, but this is not confirmed by buildbot so far