* gcc.c-torture/execute/va-arg-15.x: New file. Fails on
mips-sgi-irix6.* because the MIPS ABI passes floating-point
parameters in registers, and there is no way for a varargs
function to know in which order the integer and floating-point
parameters should be interleaved when they are placed on the
stack.
* gcc.c-torture/execute/va-arg-16.x: Likewise.
* gcc.c-torture/execute/va-arg-17.x: Likewise.