Cleaning and adding tests for Session

Adding tests for Session `destroy`, `update` and `delete` methods. No changes for code under test.
Merge pull request #14433 from adomokos/cleaning_up_and_adding_session_tests

Cleaning up and adding tests for Session
only dump schema information if migration table exists. Closes #14217
Merge pull request #14423 from yakko/persistence-touches-many

ActiveRecord#touch should accept multiple attributes

Conflicts:
	activerecord/CHANGELOG.md
Improve touch docs with extra attributes passed in [ci skip]
Check if the output is empty rather than asserting for equality

Also fix indent of test block.
Remove some indirection in rake dbs test

Just pass in the expected database as argument rather than "caching"
it in a hash and using the hash in the helper methods.
Postgres schema: Constrain sequence search classid

The pk_an_sequence_for query previously joined against pg_class's oid
for rows in pg_depend, but pg_depend's objid may point to other system
tables, such as pg_attrdef.  If a row in one of those other tables
coincidentally has the same oid as an (unrelated) sequence, that
sequence name may be returned instead of the real one.

This ensures that only the pg_depend entries pointing to pg_class are
considered.
Remove extra indirection for testing exceptions and messages

assert_raise + assert_equal on the returned exception message work
just fine, there is no need for extra work, specially like this overly
complicated helper.
Merge pull request #12955 from joshwilliams/master

Postgres schema: Constrain sequence search classid
The digest option is no longer honoured since Rails 3.0 [ci skip]

Closes #8513
Deprecate Class#superclass_delegating_accessor
Merge pull request #14271 from akshay-vishnoi/fixes

Deprecate superclass_delegating_accessor, use class_attribute instead.
Warning removed (...) interpreted as grouped expression
Merge pull request #14436 from arunagw/aa-warning-removed-grouped-expression

Warning removed (...) interpreted as grouped expression
test for structure:dump without schema information table. refs eafec46

This is a test case for the fix provided in eafec4694c5b37eff9d83b1188b8e331fa6027fa
Extract with_example_table into helper method.

This setups the helper method which other tests can benefit from.
Merge pull request #14400 from tgxworld/ensure_tables_are_dropped_after_test

Drop custom tables after each test.
Mention required glob param name in match docs for mapper

THe match documentation doesn't mention any requirement of the
parameter name requirement for matches. However, including a
bare glob character without a variable assignment causes a
parse error.
fix log_tags request object grammar