compiler: initialize gogo fields

A couple of the data members in the Gogo class were not
being initialized properly. This was causing "uninitialized value"
errors during Valgrind memcheck runs. This patch insures that
all of the fields receive an initial value.

Change-Id: I9a14d6390b52d56a76ba833bdff5b9e184319794
Reviewed-on: https://go-review.googlesource.com/38470
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2 files changed