Merged PRs

dolt

2454: go/cmd/dolt: commands/sqlserver: Add configuration for disabling MULTI_STATEMENTS support on the server.
Currently sql-server parses some MULTI_STATEMENTS incorrectly, in particular
statements that include substatements get split up incorrectly. This adds
server configuration for the yaml config, so that multi-statement handling can
be disabled server-side. This will allow things like CREATE TRIGGERs submitted
with a client that advertises MULTI_STATEMENTS support to work correctly with
Dolt sql-server. However, if the client actually sends a multi-statement in
this mode, even two SELECTs separated by a ';', for example, while the server
is running in this mode, it will not work.
To enable, place:
```
behavior:
  disable_client_multi_statements: false
```
in the config.yaml for the server.
2435: Adding columns to primary key now adds not null constraint
Also added a test case to ensure adding not null constraint to primary key column does nothing.

649: server: Add option to Config to DisableClientMultiStatements.
648: Added check for conflicting column definitions
Checks for attempt to create primary key on nullable column
646: Faster integral type conversions.
We spend up to 10% of sysbench tests in this function.
645: Clean up some unnecessary context creations, which can be expensive.

94: Add null to supported syntax for column definitions
93: go/mysql/conn.go: Add a way to disable client_multi_statements handling on a per-connection basis.
Conn's handling of CLIENT_MULTI_STATEMENTS is currently wrong for packets that
contain statements which can include other statements (e.g., CREATE TRIGGER).
Add a way for an integrator to disable it for now.
92: Add support for empty tuple in INSERT INTO ... VALUES ()
Now correctly parses
insert into test_tb values ()
insert into test_tb () values ()
insert into test_tb values (), (), ...
insert into test_tb () values (), (), ...