bin(run): specify -target for zig test (#71)

Four recent commits [1][2][3][4] tried to speed up running user
solutions in production, but weren't sufficient. Continue trying.

With Exercism's test runner architecture, the x86_64 CPU that creates
the cache is likely to have different features than the x86_64 CPU that
runs `zig test` in production. If that meant that Zig couldn't use the
cache, this commit might help.

This commit produces the below diff to a `builtin.zig` file in a
`/home/ziggy/.cache/zig/o/` subdirectory in the image. Note the reduced
set of CPU features.

    @@ -12,66 +12,22 @@ pub const single_threaded = false;
     pub const abi = std.Target.Abi.musl;
     pub const cpu: std.Target.Cpu = .{
         .arch = .x86_64,
    -    .model = &std.Target.x86.cpu.icelake_server,
    +    .model = &std.Target.x86.cpu.x86_64,
         .features = std.Target.x86.featureSet(&[_]std.Target.x86.Feature{
             .@"64bit",
    -        .adx,
    -        .aes,
    -        .allow_light_256_bit,
    -        .avx,
    -        .avx2,
    -        .avx512bw,
    -        .avx512cd,
    -        .avx512dq,
    -        .avx512f,
    -        .avx512vl,
    -        .bmi,
    -        .bmi2,
    -        .clflushopt,
             .cmov,
    -        .crc32,
    -        .cx16,
             .cx8,
    -        .ermsb,
    -        .f16c,
    -        .fast_15bytenop,
    -        .fast_gather,
    -        .fast_scalar_fsqrt,
    -        .fast_shld_rotate,
    -        .fast_variable_crosslane_shuffle,
    -        .fast_variable_perlane_shuffle,
    -        .fast_vector_fsqrt,
    -        .fma,
    -        .fsgsbase,
    -        .fsrm,
             .fxsr,
             .idivq_to_divl,
    -        .invpcid,
    -        .lzcnt,
             .macrofusion,
             .mmx,
    -        .movbe,
             .nopl,
    -        .pclmul,
    -        .popcnt,
    -        .prefer_256_bit,
    -        .prfchw,
    -        .rdrnd,
    -        .rdseed,
    -        .rtm,
    -        .sahf,
    +        .slow_3ops_lea,
    +        .slow_incdec,
             .sse,
             .sse2,
    -        .sse3,
    -        .sse4_1,
    -        .sse4_2,
    -        .ssse3,
             .vzeroupper,
             .x87,
    -        .xsave,
    -        .xsavec,
    -        .xsaveopt,
    -        .xsaves,
         }),
     };
     pub const os = std.Target.Os{
    @@ -79,14 +35,14 @@ pub const os = std.Target.Os{
         .version_range = .{ .linux = .{
             .range = .{
                 .min = .{
    -                .major = 5,
    -                .minor = 15,
    +                .major = 3,
    +                .minor = 16,
                     .patch = 0,
                 },
                 .max = .{
                     .major = 5,
    -                .minor = 15,
    -                .patch = 0,
    +                .minor = 10,
    +                .patch = 81,
                 },
             },

Refs: #63

[1] 82b56af, 2023-08-23, ".dockerignore, Dockerfile: add a zig cache"
[2] b8b9d02, 2023-08-27, "Dockerfile, bin(run-tests), tests: set USER"
[3] 3f2c0c2, 2023-08-27, "Dockerfile: create zig cache later"
[4] 0636420, 2023-08-27, "Dockerfile: create zig cache via run.sh, not zig test"

Author: ee7

bin/run.sh

@@ -37,7 +37,7 @@ cd "${solution_dir}" || exit 1
 
 # Run the tests for the provided implementation file and redirect stdout and
 # stderr to capture it
-test_output=$(zig test "${test_file}" 2>&1)
+test_output=$(zig test -target x86_64-linux-musl "${test_file}" 2>&1)
 exit_code=$?
 
 cd "${start_dir}" || exit 1