db.mysql query and real_query with ConnectionFlag.client_multi_statements makes the Connection instance useless

[einar-hjortdal]

Describe the bug

When creating a mysql.Connection using the ConnectionFlag.client_multi_statements, executing a query with multiple statements returns multiple resoluts.
The mysql wrapper lacks the ability to fetch all the results, because it does not wrap mysql_more_results() nor mysql_next_result().
Because these results aren't fetched, they remain allocated and the connection cannot be reused for any new statement without triggering a V panic: Commands out of sync; you can't run this command now; code: 2014
This problem forces to create independent connections whenever a query with multiple statements needs to be run.

Expected Behavior

Results should be able to be fetched and memory cleared.
The execution of a new query in the same connection should be possible.

Current Behavior

V panic: Commands out of sync; you can't run this command now; code: 2014

Reproduction Steps

file_data := os.read_file(file_path)!
mysql_conn.real_query(file_data)!
// Here one would loop through all results until no more results are available
// and then call mysql_free_result()
mysql_conn.real_query(query_string)!

Possible Solution

Wrap mysql_more_results() nor mysql_next_result().

Ideally the functions available already should include these functions and return an array of results instead, calling mysql_free_result() automatically. This is because mysql_free_result() requires an unsafe block which is no good for basic V users.

Additional Information/Context

No response

V version

Current V version: V 0.3.3 0a8a0fd, timestamp: 2023-03-25 14:38:47 +0200

Environment details (OS name and version, etc.)

V full version: V 0.3.3 ee4150f.c4b34c9
OS: linux, Linux version 5.14.0-162.23.1.el9_1.x86_64 (mockbuild@pp-el9) (gcc (GCC) 11.3.1 20220421 (Red Hat 11.3.1-2), GNU ld version 2.35.2-24.el9) #1 SMP PREEMPT_DYNAMIC Wed Apr 12 16:23:09 UTC 2023
Processor: 4 cpus, 64bit, little endian, Intel(R) Core(TM) i3-5005U CPU @ 2.00GHz

getwd: /home/coachonko/Documents/projects/vlang/peony
vexe: /home/coachonko/.local/lib64/v/v
vexe mtime: 2023-04-26 09:47:45

vroot: OK, value: /home/coachonko/.local/lib64/v
VMODULES: OK, value: /home/coachonko/.vmodules
VTMP: OK, value: /tmp/v_1000

Git version: git version 2.31.1
Git vroot status: weekly.2023.15-62-gc4b34c94
.git/config present: true

CC version: cc (GCC) 11.3.1 20220421 (Red Hat 11.3.1-2)
thirdparty/tcc status: thirdparty-linux-amd64 12f392c3