compiler: change Expression export to use Export_function_body

In preparation for writing expressions to inline function bodies,
change the existing expression export code to use Export_function_body
rather than Export.  Adjust existing expression exporters accordingly.

This is a refactoring that doesn't affect compiler output.

Change-Id: I998dae2b3bdf039b7bea636b1118b1bc2d5106fd
Reviewed-by: Than McIntosh <>
Reviewed-by: Cherry Zhang <>
6 files changed