build: run with a different version of go

Change-Id: I0cc5a9cb6b6b834885a54ad4c99e0cdefc476473
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/292705
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

build/Dockerfile

@@ -1,6 +1,6 @@
 # This Docker container is used for testing on GCB.
-
-FROM golang:1.15 AS gobuilder
+ARG GOVERSION=1
+FROM golang:${GOVERSION} AS gobuilder
 
 ENV GO111MODULE on
 ENV GOBIN /gobin
@@ -26,7 +26,7 @@ COPY --from=gobuilder /usr/local/go /usr/local/go
 ENV PATH /workspace/vscodego/go/bin:/go/bin:/usr/local/go/bin:${PATH}
 ENV DEBIAN_FRONTEND noninteractive
 
-RUN apt-get update && apt-get install -y libnss3 libgtk-3-dev libxss1 libasound2 xvfb libsecret-1-0
+RUN apt-get -qq update && apt-get install -qq -y libnss3 libgtk-3-dev libxss1 libasound2 xvfb libsecret-1-0 > /dev/null
 RUN npm install -g typescript vsce
 
 WORKDIR /workspace

build/all.bash

@@ -59,7 +59,8 @@ run_test() {
 
 run_test_in_docker() {
   echo "**** Building the docker image ***"
-  docker build -t vscode-test-env -f ./build/Dockerfile .
+  docker build -t vscode-test-env ${GOVERSION:+ --build-arg GOVERSION="${GOVERSION}"} -f ./build/Dockerfile .
+
   # For debug tests, we need ptrace.
   docker run --cap-add SYS_PTRACE --workdir=/workspace -v "$(pwd):/workspace" vscode-test-env ci
 }