The fixes to set the proper widths of the fields broke the heights.

It removed the defer() call and replaced it with a throttle(). The

defer() is important to the calculations, though, since we schedule a

layout resize after closing CodeMirror fields but before all layout has

settled.
This restores the original _scheduleResizeLayout() function and adds the

throttle there.

Tested adding a lot of text to the Description field and closing it. It no

longer resulted in the text fields overflowing out of the review request box.
Tested adding lots of text to the Branch field. Didn't see it cause any

overflow issues.
Resized the window. Didn't see any performance issues.