CLN: remove unnecessary alias (pandas-dev#32786)

Author: jbrockmendel

pandas/core/internals/managers.py

@@ -825,17 +825,15 @@ def as_array(self, transpose: bool = False) -> np.ndarray:
             arr = np.empty(self.shape, dtype=float)
             return arr.transpose() if transpose else arr
 
-        mgr = self
-
-        if self._is_single_block and mgr.blocks[0].is_datetimetz:
+        if self._is_single_block and self.blocks[0].is_datetimetz:
             # TODO(Block.get_values): Make DatetimeTZBlock.get_values
             # always be object dtype. Some callers seem to want the
             # DatetimeArray (previously DTI)
-            arr = mgr.blocks[0].get_values(dtype=object)
+            arr = self.blocks[0].get_values(dtype=object)
         elif self._is_single_block or not self.is_mixed_type:
-            arr = np.asarray(mgr.blocks[0].get_values())
+            arr = np.asarray(self.blocks[0].get_values())
         else:
-            arr = mgr._interleave()
+            arr = self._interleave()
 
         return arr.transpose() if transpose else arr