1) For the code space estimate, exclude everything except code.
2) Add some static code size per function.
3) Add some static code size per module.
4) Include signature zone memory.

R=mstarzinger@chromium.org

Change-Id: Ifa9ac347edf98c2e63ab3201a64ac2e0a3de28e5
Reviewed-on: https://chromium-review.googlesource.com/c/1118263Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57436}