log,sync: fix macos CI failure when log.ThreadSafeLog is used explicitly in v download

[spytheman]

• log,sync: fix macos failure with log.ThreadSafeLog
• log: add missing free(x.mu), since now mu is heap allocated

[huly-for-github]

Connected to Huly®: V_0.6-22038

[spytheman]

Fixes failures spotted on the CI:

V panic: Invalid argument
2025-01-29T23:51:52.037806Z [INFO ] Downloading [1/1] from url: https://github.com/vlang/v/releases/latest/download/v_macos_x86_64.zip to ./v_macos_x86_64.zip ...
v hash: ceaa5d2
2025-01-29T23:51:53.820915Z [INFO ]  Finished downloading file: ./v_macos_x86_64.zip .
0   vdownload                           0x000000010c235dd0 sync__Mutex_init + 0
2025-01-29T23:51:53.820926Z [INFO ]                       size: 15705238 bytes
1   vdownload                           0x000000010c235eda sync__Mutex_destroy + 42
2   vdownload                           0x000000010c1feef2 log__ThreadSafeLog_free + 34
3   vdownload                           0x000000010c23680f log__free_logger + 63
4   vdownload                           0x000000010c237b53 log__deinit + 19
5   libsystem_c.dylib                   0x00007ff8127d7ba8 __cxa_finalize_ranges + 416
6   libsystem_c.dylib                   0x00007ff8127d79bb exit + 35
7   libdyld.dylib                       0x00007ff81291d8d3 _ZNK5dyld416LibSystemHelpers4exitEi + 11
8   dyld                                0x00007ff8125ab44d start + 1949
2025-01-29T23:51:54.298673Z [INFO ]                     SHA256: 3d8a20faa69c848600ead1e1383f78726d413770972dce076aa4ce5c69283f00
Downloaded: 1 file(s) . Elapsed time: 2.260s . Errors: 0 .

https://github.com/vlang/v/actions/runs/13042647177/job/36392029435