Don't manually invalidate cached lines in _update_transScale.

Resetting transScale just above will invalidate any nodes that depend on
it as well.  (The manual line invalidation came in in ff3c65f to "fix
log/linear toggle", but that toggle clearly works fine even with this
removal; I assume that transform invalidation became better since then.)

Author: anntzer

lib/matplotlib/axes/_base.py

@@ -1079,13 +1079,6 @@ def _update_transScale(self):
         self.transScale.set(
             mtransforms.blended_transform_factory(
                 self.xaxis.get_transform(), self.yaxis.get_transform()))
-        for line in self._children:
-            if not isinstance(line, mlines.Line2D):
-                continue
-            try:
-                line._transformed_path.invalidate()
-            except AttributeError:
-                pass
 
     def get_position(self, original=False):
         """