isl-ast-gen-if.c (main): Increase size of a array to allow a[50] to be a valid location.

	* gcc.dg/graphite/isl-ast-gen-if.c (main): Increase size of a
	array to allow a[50] to be a valid location.

From-SVN: r224743

gcc/testsuite/gcc.dg/graphite/isl-ast-gen-if-1.c

@@ -28,7 +28,7 @@ extern void abort ();
 int
 main (void)
 {
-  int a[50];
+  int a[51]; /* NB This size allows foo's first iteration to write to a[50].  */
   foo (a, 50);
   int res = array_sum (a);
   if (res != 49)