Add tests for when the program verifies

In this case, the status is inconclusive until completion, at which
point success will be reported by CBMC overall.

Author: Thomas Kiley

regression/cbmc-incr-oneloop/valid-asserts/test.c

@@ -0,0 +1,8 @@
+int main()
+{
+  for(int i = 0; i < 10; ++i)
+  {
+    assert(i != 10);
+  }
+  return 0;
+}

regression/cbmc-incr-oneloop/valid-asserts/test.desc

@@ -0,0 +1,16 @@
+CORE
+test.c
+--incremental-loop main.0
+activate-multi-line-match
+Incremental status: INCONCLUSIVE\nCurrent unwinding: 2
+Incremental status: INCONCLUSIVE\nCurrent unwinding: 10
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
+^warning: ignoring
+Incremental status: SUCCESS
+--
+Check that for valid asserts, the incremental status is inconclusive
+as it is only after the incrementer has been stopped we conclude is
+verified.