vulkan system dep: determine version on cross builds

Currently, the vulkan system dep detects its vulkan version by building
and running:

int main() {
    printf("%i.%i.%i", VK_VERSION_MAJOR(VK_HEADER_VERSION_COMPLETE),
                       VK_VERSION_MINOR(VK_HEADER_VERSION_COMPLETE),
                       VK_VERSION_PATCH(VK_HEADER_VERSION_COMPLETE));
    return 0;
}

this causes cross builds that do not have the possibility of running on
the build machine to evaluate the vulkan dependency with an 'Unknown'
version.

Instead of evaluating beforementioned piece of C code, the new
implementation will instead use cc.compute_int to evaluate the three
preprocessor macros.
This is relativly expensive for cross builds right now but further
optimizations can be made. See #13910 for more details.

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