S/390: Fix vec-cmp-2 testcase

S/390: Fix vec-cmp-2 testcase

The functions all call foo and therefore need a stack frame what makes
them subject to shrink wrapping.  Also all the additional instructions
in the function body makes it fragile wrt instruction scheduling.  Just
set a global variable instead to circumvent this.

gcc/testsuite/ChangeLog:

2017-10-18  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* gcc.target/s390/zvector/vec-cmp-2.c
	(all_eq_double, all_ne_double, all_gt_double)
	(all_lt_double, all_ge_double, all_le_double)
	(any_eq_double, any_ne_double, any_gt_double)
	(any_lt_double, any_ge_double, any_le_double)
	(all_eq_int, all_ne_int, all_gt_int)
	(all_lt_int, all_ge_int, all_le_int)
	(any_eq_int, any_ne_int, any_gt_int)
	(any_lt_int, any_ge_int, any_le_int): Set global variable instead
	of calling foo().  Fix return type.

From-SVN: r253846