fix(connection-manager): only use close to shutdown (#8789)

lib/dialects/abstract/connection-manager.js

@@ -43,10 +43,6 @@ class ConnectionManager {
       Promise
       Promise
     });
     });
 
 
-    process.on('beforeExit', () => {
-      this._onProcessExit.call(this);
-    });
-
     this.initPools();
     this.initPools();
   }
   }