Fix reinterpret<T> for 64-bit types

[juliusikkala]

Fixes the upper 32 bits of 64-bit values in AnyValue packing. The low 32 bits were repeated in the high bits. This caused reinterpret<T> to behave incorrectly for basic 64-bit types.

An example of the issue:

export __extern_cpp int main()
{
    int64_t ptr = 0x0123456789ABCDEF;
    uint64_t ptr2 = reinterpret<uint64_t>(ptr);
    printf("%lX\n", ptr);
    printf("%lX\n", ptr2);
    return 0;
}

prints:

123456789ABCDEF
89ABCDEF89ABCDEF

This also affects pointers, so reinterpreting addresses broke them.

[csyonghe]

Thanks for fixing this!