Implement mysqli_execute_query()

[kamil-tekiela]

This is the implementation for RFC https://wiki.php.net/rfc/mysqli_execute_query

Key notes:

• While the code was copied from prepare, execute, and get_result, there were some adjustments and it's not identical.
• It returns true on success when no result is present. It resembles more mysqli_query than get_result.
• The authors of the RFC decided that it was a bug that affected_rows was reset to -1. The value is now preserved in the $mysql object.
• Regarding performance: a quick artificial benchmark showed 6% decrease in execution time when compared to calling all 3 methods separately.
• As the mysqli_stmt object is never exposed, special attention was put to error handling and ensuring the memory is freed when necessary. The error messages are preserved on the $mysql object for when automatic error reporting is switched off.

[cmb69]

Thank you! This looks good to me.