i386: Update PR target/95021 tests

Also pass -mpreferred-stack-boundary=4 -mno-stackrealign to avoid
disabling STV by:

  /* Disable STV if -mpreferred-stack-boundary={2,3} or
     -mincoming-stack-boundary={2,3} or -mstackrealign - the needed
     stack realignment will be extra cost the pass doesn't take into
     account and the pass can't realign the stack.  */
  if (ix86_preferred_stack_boundary < 128
      || ix86_incoming_stack_boundary < 128
      || opts->x_ix86_force_align_arg_pointer)
    opts->x_target_flags &= ~MASK_STV;

	PR target/98676
	* gcc.target/i386/pr95021-1.c: Add -mpreferred-stack-boundary=4
	-mno-stackrealign.
	* gcc.target/i386/pr95021-3.c: Likewise.