service: fetch Golang lints produced by Golint.

Currently, the BuildLinter class can fetch clang-tidy and cargo clippy
lints. This change adds logic for fetching Golint lints that are
generated when a package using the cros-go eclass is built. In order to
support the addition of Golanf linting, it also modifies other chromite
files that use the BuildLinter class and the emerge_with_linting method.

BUG=b:236715258
TEST=ran lint_package CLI tool

Change-Id: Ia0210cdc5f354a91a134aef4a808bbc4c93bc0fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3723171
Commit-Queue: Uwem Wilson <uwemwilson@google.com>
Reviewed-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Jordan Abrahams-Whitehead <ajordanr@google.com>
Tested-by: Uwem Wilson <uwemwilson@google.com>
Reviewed-by: Ryan Beltran <ryanbeltran@chromium.org>
diff --git a/api/controller/toolchain.py b/api/controller/toolchain.py
index b166d82..33ec155 100644
--- a/api/controller/toolchain.py
+++ b/api/controller/toolchain.py
@@ -351,7 +351,9 @@
       input_proto.sysroot.path,
       differential=input_proto.filter_modified)
 
-  findings = build_linter.emerge_with_linting(use_clippy=True, use_tidy=True)
+  findings = build_linter.emerge_with_linting(use_clippy=True,
+                                              use_tidy=True,
+                                              use_golint=True)
 
   for finding in findings:
     locations = []