Fix the problems exposed by the callingconv1.d test case. The first was that unless otherwise specified, inputs are assumed to be in registers even if they specify a "matching output" that's in memory. While testing that fix, I also ran into a bug causing the generated "matching output" for any input was always the first one instead of the correct one.

module tangotests.files1;

//import tango.io.Stdout;
import tango.io.File;

void main()
{
    auto file = new File("files1.output");
    char[] str = "hello world from files1 test\n";
    void[] data = cast(void[])str;
    file.write(str);
}