Temporarily pin tests' Code version to 1.67.2

Because 1.68.0 breaks!

Author: andyleejordan

test/runTests.ts

@@ -25,7 +25,7 @@ async function main() {
             launchArgs: ["--disable-extensions", "./test"],
             // This is necessary because the tests fail if more than once
             // instance of Code is running.
-            version: "insiders"
+            version: "1.67.2"
         });
     } catch (err) {
         // tslint:disable-next-line:no-console