Simplify and enhance vscode dockerfile to use nightly ts in ts extension, too

Author: weswigham

tests/cases/docker/vscode/Dockerfile

@@ -1,4 +1,4 @@
-# vscode only supports node 8 :(
+# vscode only supports older node
 FROM node:10
 RUN apt-get update
 RUN apt-get install libsecret-1-dev libx11-dev libxkbfile-dev -y
@@ -7,12 +7,12 @@ RUN git clone https://github.com/microsoft/vscode.git /vscode
 WORKDIR /vscode
 RUN git pull
 COPY --from=typescript/typescript /typescript/typescript-*.tgz /typescript.tgz
-RUN mkdir /typescript
-RUN tar -xzvf /typescript.tgz -C /typescript
 WORKDIR /vscode/build
-RUN yarn add typescript@/typescript/package
+RUN yarn add typescript@/typescript.tgz
+WORKDIR /vscode/extensions
+RUN yarn add typescript@/typescript.tgz
 WORKDIR /vscode
-RUN yarn add typescript@/typescript/package
+RUN yarn add typescript@/typescript.tgz
 RUN yarn
 ENTRYPOINT [ "yarn" ]
 # Build