Where possible, avoid freeing buffers allocated for vdbe memory cells in case they can be reused. (CVS 4783)

FossilOrigin-Name: 990237e27e417aff3dbf05784b716c21f3761a3a

src/vdbeapi.c

@@ -944,6 +944,7 @@ int sqlite3_bind_value(sqlite3_stmt *pStmt, int i, const sqlite3_value *pValue){
   if( rc==SQLITE_OK ){
     rc = sqlite3VdbeMemCopy(&p->aVar[i-1], pValue);
   }
+  rc = sqlite3ApiExit(p->db, rc);
   sqlite3_mutex_leave(p->db->mutex);
   return rc;
 }