Per review by Serg, include start row with new line.
We are hoping we haven't annoyed people that prefered the old
way.
Adding an option for new lines seems like over-engineering in advance.
So if there are complaints, let them be known (JIRA), and we'll add
this under an option.
Test cases updated.
Currently, mysqldump --extended-insert outputs all rows on a single line,
which makes it difficult to use with various Unix command-line utilities
such as grep and diff.
We change mysqldump to emit a linebreak between each row, that would make
it easier to work with, without significantly affecting dump or restore
performance, or affecting compatibility.
Closes: #1865
Remove usage of deprecated variable storage_engine. It was deprecated in 5.5 but
it never issued a deprecation warning. Make it issue a warning in 10.5.1.
Replaced with default_storage_engine.
