Revert "Simplify the conditionals used for learning rate calculation …

…for `ConstantLR` learning rate scheduler (#109785)"

This reverts commit 83283b4.

Reverted #109785 on behalf of https://github.com/PaliC due to causing macos errors as per https://hud.pytorch.org/pytorch/pytorch/commit/83283b4f0dc2032a31f9a80c7aa40e3e552ec944 ([comment](#109785 (comment)))

torch/optim/lr_scheduler.py

@@ -489,10 +489,12 @@ def get_lr(self):
         if self.last_epoch == 0:
             return [group['lr'] * self.factor for group in self.optimizer.param_groups]
 
-        if self.last_epoch != self.total_iters:
+        if (self.last_epoch > self.total_iters or
+                (self.last_epoch != self.total_iters)):
             return [group['lr'] for group in self.optimizer.param_groups]
 
-        return [group['lr'] * (1.0 / self.factor) for group in self.optimizer.param_groups]
+        if (self.last_epoch == self.total_iters):
+            return [group['lr'] * (1.0 / self.factor) for group in self.optimizer.param_groups]
 
     def _get_closed_form_lr(self):
         return [base_lr * (self.factor + (self.last_epoch >= self.total_iters) * (1 - self.factor))