The stack frame includes the callee args section. At the point where
we were checking the frame size, that part of the frame had not been
computed yet. Move the check later so we can include the callee args size.

Fixes #20780
Update #25507

Change-Id: Iab97cb89b3a24f8ca19b9123ef2a111d6850c3fe
Reviewed-on: https://go-review.googlesource.com/115195
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>