[ticket/11469] Split tests and skip multi_insert if unavailable

PHPBB3-11469
[ticket/11469] Check return values of the functions

PHPBB3-11469
[ticket/11469] Cast $result to boolean in insert_all()

|= returns integer values

PHPBB3-11469
Merge remote-tracking branch 'nickvergessen/ticket/bantu/11469-2' into ticket/11469

* nickvergessen/ticket/bantu/11469-2:
  [ticket/11469] Cast $result to boolean in insert_all()
  [ticket/11469] Check return values of the functions
  [ticket/11469] Split tests and skip multi_insert if unavailable
[ticket/11469] Move protected method to end of test file.

PHPBB3-11469
[ticket/11469] Dot not repeat array with three rows.

PHPBB3-11469
[ticket/11469] Do not repeat row generation.

PHPBB3-11469
[ticket/11469] Use buffer with a single element instead of extra code path.

PHPBB3-11469
[ticket/11469] Use multi insert property from DB. Do not copy value to buffer.

PHPBB3-11469
[ticket/11469] Use setUp() to setup DB and a buffer with size 2.

PHPBB3-11469
[ticket/11469] Do not repeat assert_config_count(2). Also move to setUp().

PHPBB3-11469
[ticket/11469] Fix spacing in getDataSet().

PHPBB3-11469
[ticket/11469] Refactor get_three_rows() into get_rows($n).

PHPBB3-11469
[ticket/11469] Do not repeat markTestSkipped() message.

PHPBB3-11469
[ticket/11469] Remove comments. Method names should be good enough now.

PHPBB3-11469
[ticket/11469] Add more table status assertions.

PHPBB3-11469
[ticket/11469] Add comment about using bitwise operator.

PHPBB3-11469