I'm not sure why these tests have failed - I've heard other people have successfully submitted Windows 8 apps made in Construct 2 and had them approved.
App launch test: no idea why the app would fail to stop, does it do anything CPU intensive that could hang it on shutdown?
Bytecode generation: no idea about this, maybe there's a syntax error in the JS, might be worth checking it works in a browser with no errors in the browser console
Performance suspend: this is definitely supported in the engine, so again odd that it would report this.
Note: are you using the third party 'Metro' object by any chance? This has some problems that might be fixed by using the official plugin.