Adjust one Ada test

Recent change modified how the loops are created, with the first
iteration being extracted out of the loops in the 2 test cases.
Adjust the text to match from the unroll dump.

gcc/testsuite/ChangeLog:

	* gnat.dg/unroll3.adb: Adjust.

gcc/testsuite/gnat.dg/unroll3.adb

@@ -23,4 +23,4 @@ package body Unroll3 is
 
 end Unroll3;
 
--- { dg-final { scan-tree-dump-times "loop with 3 iterations completely unrolled" 2 "cunroll" } }
+-- { dg-final { scan-tree-dump-times "loop with 2 iterations completely unrolled" 2 "cunroll" } }