MDEV-7133: InnoDB: Assertion failure in dict_tf_is_valid

Problem is that page compressed tables currently require atomic_blobs and
that feature is not availabe currently for row_format=redundant.

Fix: Disallow page compressed create option if table row_format=redundant.
Sharing similar code between Item_func_ifnull and Item_func_if
MDEV-7005 NULLIF does not work as documented
MDEV-7146 NULLIF returns unexpected result with a YEAR field
Deriving Item_bool_func from Item_bool_func2.
Removing some duplicate code: deriving Item_func_opt_neg from Item_bool_func.
MDEV-7053: WSREP_STATUS & WSREP_MEMBERSHIP I_S tables

wsrep_info INFORMATION_SCHEMA plugin to provide WSREP_STATUS
and WSREP_MEMBERSHIP tables.
MDEV-7161: Build failure in buildbot on work-amd64-valgrind

Fix for embedded build failure.
Also added wsrep_info plugin library to server debian package.
MDEV-7166: innodb.innodb-page_compression_zip fails in buildbot

Analysis: If innodb_use_trim is not enabled or system does not
support fallocate to make persistent trim, we should always
write full page not only partial pages.
MDEV-7171 funcs_1.is_tables_is and main.information_schema-big fail in buildbot.
        test results updated with the new GIS-related IS tables.
MDEV-7164: innodb.innodb-alter-table-disk-full fails in buildbot on Windows

Analysis: Test case uses Linux specific error codes.

Fix: Can't run test case with Windows currently because requires
to inject error to system.
MDEV-7168: Tests innodb.innodb_stats_create_table
innodb.innodb_stats_drop_locked fail and
innodb.innodb_stats_fetch_nonexistent fails in buildbot on Windows

Analysis: Problem is that innodb_stats_create_on_corrupted
test renames mysql.innodb.index_stats and all the rest
are dependend on this table.

Fix: After rename back to original, restart mysqld to
make sure that table is correct.
MDEV-7169: innodb.innodb_bug14147491 fails in buildbot on Windows

  Problem is that test could open Microsoft C++ Client Debugger
  windows with abort exceptin. Lets not try to test this on
  windows.
MDEV-7167: innodb.innodb_bug12902967 fails in buildbot on Windows

Problem is that there is additional error message from function
that is not really needed now.
MDEV-7181: innodb.innodb_defrag_concurrent fails in buildbot

Problem was that test tried to calculate number of pages on
buffer pool and operations done to them. This is not realible
way on buildbot.
Merge branch '10.1' into bb-10.1-encryption