The test case for reproducing MDEV-14126 demonstrates that InnoDB can
end up with an index tree where a non-leaf page has only one child page.

The test case innodb.innodb_bug14676111 demonstrates that such pages
are sometimes unavoidable, because InnoDB does not implement any sort
of B-tree rotation.

But, there is no reason to allow a root page with only one child page.

btr_cur_node_ptr_delete(): Replaces btr_node_ptr_delete().

btr_page_get_father(): Declare globally.

btr_discard_only_page_on_level(): Declare with ATTRIBUTE_COLD.
It turns out that this function is not covered by the
innodb.innodb_bug14676111 test case after all.

btr_discard_page(): If the root page ends up having only one child
page, shrink the tree by invoking btr_lift_page_up().

This is follow-up to commit 1bd98154.

Backport some changes to B-tree page accessor functions from 10.3,
including changing page_get_n_recs() to return uint16_t.

If an index page becomes empty, btr_page_empty() should be called.

The predicate page_is_root(), which was added in MariaDB Server 10.2.2,
is based on a wrong assumption.

Under some circumstances, InnoDB can transform B-trees into a degenerate
state where a non-leaf page has no sibling pages. Because of this,
we cannot assume that a page that has no siblings is the root page.
This bug will be tracked as MDEV-19022.

Because of the bug that may affect many InnoDB data files, we must remove
and replace the wrong predicate. Using the wrong predicate can cause
corruption. A leaf page is not allowed to be empty except if it is the
root page, and the entire table is empty.

MariaDB before MDEV-5800 in version 10.2.2 did not support
indexed virtual columns. Non-persistent virtual columns were
hidden from storage engines. Only starting with MDEV-5800, InnoDB
would create internal metadata on virtual columns.

Similar to what was done in MDEV-18084 and MDEV-18960, we adjust two more
code paths for the old tables.

ha_innobase::build_template(): Do not invoke
dict_index_contains_col_or_prefix() for virtual columns if InnoDB
does not store the metadata.

innobase_build_col_map(): Relax an assertion about the number of columns.

ha_innobase::omits_virtual_cols(): Renamed from omits_virtual_cols().

Adding tests to cover how SEQUENCE related statements work in combination
with the slow log configuration commands.

new location for CPackRPM.cmake

MDEV-18904 Assertion `m_part_spec.start_part >= m_part_spec.end_part' failed in ha_partition::index_read_idx_map

Remove the DBUG_ASSERT

found by @marko

don't link with libnuma in release builds

MDEV-18224 MTR's internal check of the test case 'innodb.recovery_shutdown' failed due to extra #sql-ib*.ibd files

The test innodb.recovery_shutdown would occasionally fail,
because recovered incomplete transactions would be conflicting
with DROP TABLE, causing the background drop table queue to be invoked.

Add a slow shutdown before dropping the tables, so that the
recovered transactions will be rolled back. Starting with MDEV-14705,
normal shutdown would abort the rollback of recovered transactions.

Add test case for MDEV-18901 as MDEV-18967 and MDEV-18922 solves this issue

The file will be closed on line 540

Update system versioning fields before generated columns for left out
fill_record

Make buf_pool_t::io_buf_t() a more proper class.

buf_pool_t::io_buf_t::io_buf_t(): Silence the GCC 8 -Wclass-memaccess
warning for initializing slots[], which no longer is a plain old datatype
(POD) due to the std::atomic member.