Update stale comment name (#1807)

Summary:
Pull Request resolved: #1807

title

Reviewed By: lucylq

Differential Revision: D53323189

fbshipit-source-id: deba2c59316b1f6f042a669db83ae19d2e9111a2

Author: JacobSzwejbka

schema/program.fbs

@@ -67,9 +67,9 @@ table Tensor {
   // variants of non-constant Tensor ("input" and control-flow "placeholder") as a special
   // optimization to avoid holding unnecessary AllocationDetails.
   // In summary:
-  //   constant_buffer_idx > 0, pre_allocation = Null: Tensor is a constant
-  //   constant_buffer_idx = 0, pre_allocation = Non Null: Tensor is a non-constant.
-  //   constant_buffer_idx = 0, pre_allocation = Null: Tensor is a non-constant
+  //   constant_buffer_idx > 0, allocation_info = Null: Tensor is a constant
+  //   constant_buffer_idx = 0, allocation_info = Non Null: Tensor is a non-constant.
+  //   constant_buffer_idx = 0, allocation_info = Null: Tensor is a non-constant
   //     that will receive a dataptr at input time or during execution.
   //
   // Index to the program's constant buffer table, value 0 is reserved to indicate non constant