- use --install-builtin-extension arg instaed of --builtin flag to install builtin extension

- speed up installing extensions in cli

src/vs/code/node/cli.ts

@@ -23,6 +23,7 @@ function shouldSpawnCliProcess(argv: NativeParsedArgs): boolean {
 	return !!argv['install-source']
 		|| !!argv['list-extensions']
 		|| !!argv['install-extension']
+		|| !!argv['install-builtin-extension']
 		|| !!argv['uninstall-extension']
 		|| !!argv['locate-extension']
 		|| !!argv['telemetry'];