[wp] Update tests oracles

src/plugins/wp/tests/wp_plugin/oracle/post_assigns.res.oracle

@@ -36,6 +36,6 @@ Prove: true.
   /*@
      behavior typed:
        requires \separated(message + (..), &size);
-       requires \separated(message + (0 .. \at(size,Post)), &size);
+       ensures \separated(message + (0 .. \at(size,Post)), &size);
      */
   void receive(int n, char *message);

src/plugins/wp/tests/wp_typed/oracle/unit_alloc.0.res.oracle

@@ -59,3 +59,7 @@ Assume {
 Prove: !valid_rw(Malloc_0[L_y_25 <- 0], a, 1).
 
 ------------------------------------------------------------
+[wp] Warning: Memory model hypotheses for function 'h':
+  /*@ behavior typed:
+        ensures \separated(\result, &x); */
+  int *h(int x);

src/plugins/wp/tests/wp_typed/oracle/unit_alloc.1.res.oracle

@@ -59,3 +59,7 @@ Assume {
 Prove: !valid_rw(Malloc_0[L_y_25 <- 0], a, 1).
 
 ------------------------------------------------------------
+[wp] Warning: Memory model hypotheses for function 'h':
+  /*@ behavior typed_ref:
+        ensures \separated(\result, &x); */
+  int *h(int x);