Funcdepth was already int32. Make Escloopdepth
and Decldepth also int32 instead of int.

No functional changes for non-absurd code. Passes toolstash -cmp.

Change-Id: I47e145dd732b6a73cfcc6d45956df0dbccdcd999
Reviewed-on: https://go-review.googlesource.com/10129Reviewed-by: Russ Cox <rsc@golang.org>