Use `-O0` instead of `-Og` for `Debug` builds

[Alex Rønne Petersen]

zig-sdk/src/sdk/ZigCompile.cs

Lines 238 to 250 in f3f8941

 // These exact flags are treated specially by zig cc/c++. They 
 // activate Debug, ReleaseFast, ReleaseSafe, and ReleaseSmall 
 // respectively. This in turns activates a bunch of other 
 // mode-specific flags that we do not have to specify here as a 
 // result. 
 builder.AppendSwitch((_configuration, _releaseMode) switch 
 { 
     (ZigConfiguration.Debug, _) => "-Og", 
     (ZigConfiguration.Release, ZigReleaseMode.Fast) => "-O3", 
     (ZigConfiguration.Release, ZigReleaseMode.Safe) => "-O2 -fsanitize=undefined", 
     (ZigConfiguration.Release, ZigReleaseMode.Small) => "-Oz", 
     _ => throw new Exception(), 
 }); 

See: ziglang/zig#11949

[Alex Rønne Petersen]

Also review our use of -O3 vs -O2.