[tests] update test oracles

tests/syntax/oracle/array_cast_bts1099.res.oracle

 [kernel] Parsing array_cast_bts1099.i (no preprocessing)
 [kernel] array_cast_bts1099.i:12: User Error: 
-  Cast over a non-scalar type t
+  explicit cast: cast over a non-scalar type t
   10      int tab1[4];
   11      u* p = &tab1;
   12      t* p2 = (t) p;

tests/syntax/oracle/wrong-assignment.res.oracle

 [kernel] Parsing wrong-assignment.i (no preprocessing)
 [kernel] wrong-assignment.i:13: User Error: 
-  cast from ebool to _Bool
+  implicit cast: cast from ebool to _Bool
   11    void d() {
   12      // this assignment should be rejected
   13      c.a = b;