SQLite backend does not close db connection correctly

[rsk700]

Bug Description

As in code example below I open db in WAL mode, and after closing pool, "-wal" and "-shm" files not deleted (which sqlite deletes when last connection closes). I've looked at source code and only place calling sqlite3_close is:
https://github.com/launchbadge/sqlx/blob/v0.6.2/sqlx-core/src/sqlite/connection/handle.rs#L99

but it looks like it never called (I've made simple test by putting panic! in start of ConnectionHandle::drop)

related issue: #272

Minimal Reproduction

Cargo.toml:

[package]
name = "sqlitewal"
version = "0.1.0"
edition = "2021"

[dependencies]
sqlx = { version="0.6.2", features=["runtime-tokio-rustls", "sqlite"] }
tokio = { version="1", features=["macros"] }
anyhow = "1.0"

main.rs:

use sqlx::sqlite::{SqliteConnectOptions, SqliteJournalMode, SqlitePool};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let options = SqliteConnectOptions::new()
        .filename("d1.sqlite")
        .create_if_missing(true)
        .journal_mode(SqliteJournalMode::Wal);
    let pool = SqlitePool::connect_with(options).await?;
    sqlx::query("create table if not exists t1 (a text);")
        .execute(&pool)
        .await?;
    sqlx::query("insert into t1 (a) values (?)")
        .bind("aaa")
        .execute(&pool)
        .await?;
    pool.close().await;

    Ok(())
}

Info

• SQLx version: 0.6.2
• SQLx features enabled: "runtime-tokio-rustls", "sqlite"
• Database server and version: SQLite 3.31.1
• Operating system: Ubuntu 20.04.5 LTS
• rustc --version: rustc 1.66.0