Bug: Cache splits based on host platform

Describe the bug

Given the following declaration:

[
    xcodeproj(
        name = "xcodeproj-{0}-{1}".format(build_mode, ios_simulator_cpus),
        build_mode = build_mode,
        ios_simulator_cpus = ios_simulator_cpus,
        ...
    )
    for build_mode in [
        "bazel",
        "xcode",
    ]
    for ios_simulator_cpus in [
        "sim_arm64",
        "x86_64",
    ]
]

Run this on an Intel-based Mac to populate to remote cache.

bazel run //:xcodeproj-bazel-sim_arm64 -- --build_output_groups all_targets

On an Apple silicon Mac, generate an Xcode project with:

bazel run //:xcodeproj-bazel-sim_arm64

Open it, build, and see a lot of cache misses.

(10:50:06) INFO: 2529 processes: 253 remote cache hit, 1132 internal, 1144 local.

Versions

• Bazel: 6.0.0-pre.20220804.3
• rules_xcodeproj: https://github.com/buildbuddy-io/rules_xcodeproj/commit/0f0ffa7c3d01c5316b8f7f4108ece051c8426c9b
• rules_apple: d04edf4136b4818662d7126582ec257aee372339
• rules_swift: 6153a848f747e90248a8673869c49631f1323ff3