examples/test is moved to testsuite

testsuite/srg/cyclic-empty-prod/cyclic-empty-prod.gf

@@ -0,0 +1,9 @@
+cat S; E; 
+
+fun s : S ;
+fun es : E -> S -> S ;
+fun e : E ;
+
+lin s  = { s = "s" } ;
+lin es e s = { s = e.s ++ s.s } ;
+lin e = { s = [] } ;