SAC Performance Fixes (#6295)

* SAC Performance Fixes

* Small Changes

* Update sac_model.py

* fix normalize wrapper

* Update test_eager_support.py

Co-authored-by: Eric Liang <ekhliang@gmail.com>

rllib/env/normalize_actions.py

@@ -0,0 +1,21 @@
+import gym
+from gym import spaces
+import numpy as np
+
+
+class NormalizeActionWrapper(gym.ActionWrapper):
+    """Rescale the action space of the environment."""
+
+    def action(self, action):
+        if not isinstance(self.env.action_space, spaces.Box):
+            return action
+
+        # rescale the action
+        low, high = self.env.action_space.low, self.env.action_space.high
+        scaled_action = low + (action + 1.0) * (high - low) / 2.0
+        scaled_action = np.clip(scaled_action, low, high)
+
+        return scaled_action
+
+    def reverse_action(self, action):
+        raise NotImplementedError