Added Fibonacci test case

lib/wasm2cretonne-util/filetests/fibonacci.wast

@@ -0,0 +1,22 @@
+(module
+  (memory 1)
+  (func $main (local i32 i32 i32 i32)
+    (set_local 0 (i32.const 0))
+    (set_local 1 (i32.const 1))
+    (set_local 2 (i32.const 1))
+    (set_local 3 (i32.const 0))
+    (block
+    (loop
+        (br_if 1 (i32.gt_s (get_local 0) (i32.const 5)))
+        (set_local 3 (get_local 2))
+        (set_local 2 (i32.add (get_local 2) (get_local 1)))
+        (set_local 1 (get_local 3))
+        (set_local 0 (i32.add (get_local 0) (i32.const 1)))
+        (br 0)
+    )
+    )
+    (i32.store (i32.const 0) (get_local 2))
+  )
+  (start $main)
+  (data (i32.const 0) "0000")
+)