document habtm join-table name with custom prefix [ci skip].

Closes #9643.

The logic was introduced with 46492949
Merge pull request #9645 from senny/9643_habtm_wrong_table_name

document habtm join-table name with custom prefix [ci skip]
Address ActiveRecord::StatementInvalid: OCIError: ORA-00979
Change from each to each_value on hash to avoid unused variable warning
Merge pull request #9650 from yahonda/group_by_oracle

Address ActiveRecord::StatementInvalid: OCIError: ORA-00979
Merge pull request #9651 from vipulnsward/change_to_each_value_intest

Change from each to each_value on hash to avoid unused variable warning
Fixed tests for returning an instance of `Time` in the local system timezone.
Merge pull request #9653 from jetthoughts/master

Fixed tests `to_time` returning an instance of `Time` in the local system timezone.

Tests for to_time returning an instance of Time in the local system timezone did not take in account DST when they used mixed timezone declarations like 'US/Eastern' and '-0500'.

Replaced timezone with DST by timezone without DST.