[DBTNG + simpletest] missing db_select()->temporary()

Problem/Motivation

The 'DBTNG' introduced in 7.x was incomplete with regards to temporary table creation.

Proposed resolution

Allow temporary tables to be created through db_select().

Remaining tasks

User interface changes

None.

API changes

Marks db_query_temporary() as deprecated for 8.1.

Original report by @hswong3i →

Beside using db_query_range() directly, we can also use db_select()->range(); BTW, now we are missing db_select()->temporary() as it is not yet implemented, so db_query_temporary() is our only choice.

This patch add the new method db_select()->temporary(), which also coming with additional simpletest test case. Tested with MySQL + simpletest and pass.

Beta phase evaluation