Support tree artifact outputs in XCFramework rules

[luispadron]

Manual cherry-pick of: 3276c83

One thing i noticed was upstream is generating different static xcframeworks than we are, i didnt want to change that in this PR and not entirely sure which is correct.

Test from upstream:

expected_directories = {
    "ios_static_xcframework.xcframework": [
        "Info.plist",
        "ios-arm64/ios_static_xcframework.a",
        "ios-arm64/Headers/ios_static_xcframework/ios_static_xcframework.h",
        "ios-arm64/Headers/ios_static_xcframework/module.modulemap",
        "ios-arm64/Headers/ios_static_xcframework/shared.h",
        "ios-arm64_x86_64-simulator/ios_static_xcframework.a",
        "ios-arm64_x86_64-simulator/Headers/ios_static_xcframework/ios_static_xcframework.h",
        "ios-arm64_x86_64-simulator/Headers/ios_static_xcframework/module.modulemap",
        "ios-arm64_x86_64-simulator/Headers/ios_static_xcframework/shared.h",
    ],
},

Compared to what is created in master today:

expected_directories = {
    "ios_static_xcframework.xcframework": [
        "Info.plist",
        "ios-arm64/ios_static_xcframework.framework/ios_static_xcframework",
        "ios-arm64/ios_static_xcframework.framework/Headers/ios_static_xcframework.h",
        "ios-arm64/ios_static_xcframework.framework/Headers/shared.h",
        "ios-arm64/ios_static_xcframework.framework/Modules/module.modulemap",
        "ios-arm64_x86_64-simulator/ios_static_xcframework.framework/ios_static_xcframework",
        "ios-arm64_x86_64-simulator/ios_static_xcframework.framework/Headers/ios_static_xcframework.h",
        "ios-arm64_x86_64-simulator/ios_static_xcframework.framework/Headers/shared.h",
        "ios-arm64_x86_64-simulator/ios_static_xcframework.framework/Modules/module.modulemap",
    ],
},