Symlink node_modules.asar to node_modules in lib/vscode

Closes #2197.

ci/build/npm-postinstall.sh

@@ -41,6 +41,19 @@ main() {
 vscode_yarn() {
   cd lib/vscode
   yarn --production --frozen-lockfile
+
+  # VS Code needs a node_modules.asar but that's just a duplicate of stuff we
+  # already have in node_modules.
+  if [ ! -e node_modules.asar ]; then
+    if [ "${WINDIR-}" ]; then
+      # mklink takes the link name first.
+      mklink /J node_modules.asar node_modules
+    else
+      # ln takes the link name second.
+      ln -s node_modules node_modules.asar
+    fi
+  fi
+
   cd extensions
   yarn --production --frozen-lockfile
   for ext in */; do