SQL: support "simple", multi-statement queries.

[nicksrandall]

What version of Bun is running?

1.2.2

What platform is your computer?

Darwin 24.3.0 arm64 arm

What steps can reproduce the bug?

Bun's SQL implementation should only convert a query to a prepared statement if it has at least one variable (parameter). This is the only situation in where a prepared statement is needed. Otherwise, the client should just use a "simple" query which has the advantage of allowing multiple statements.

What is the expected behavior?

I would expect to be able to support multiple statements in a single query (very common for migration scripts).

What do you see instead?

I get the following error: cannot insert multiple commands into a prepared statement

Additional information

IMO, this is an essential feature for a SQL client. It's very cumbersome to do db migrations without this.