revert yield-from test

Yield-from was introduced in 3.3, so we have to catch the compile error that's raise in 3.2. :(

tests/native_tests/native_macros.hy

@@ -1,6 +1,3 @@
-(import [hy._compat [PY33]])
-(import [hy.errors [HyCompileError]])
-
 (defmacro rev [&rest body]
   "Execute the `body` statements in reverse"
   (quasiquote (do (unquote-splice (list (reversed body))))))

tests/native_tests/py3_only_tests.hy

@@ -1,13 +1,25 @@
 ;; Tests where the emited code relies on Python 3.
 ;; Conditionally included in nosetests runs.
 
+(import [hy._compat [PY33]])
+(import [hy.errors [HyCompileError]])
+
 (defn test-yield-from []
  "NATIVE: testing yield from"
-  (do (defn yield-from-test []
+
+ (try
+  (eval
+   '(do (defn yield-from-test []
           (for* [i (range 3)]
             (yield i))
           (yield-from [1 2 3]))
         (assert (= (list (yield-from-test)) [0 1 2 1 2 3]))))
+  (catch [e HyCompileError]
+    ;; Yield-from is supported in py3.3+ only
+    (assert (not PY33)))
+  (else (assert PY33))))
+
+
 
 (defn test-exception-cause []
   (try (raise ValueError :from NameError)