`AssertSz` doesn't actually do anything

It seems like AssertSz is just being silently ignored. In 0.64, I hit this issue when the JS bundle is invalid. An exception gets thrown in SystemChakraRuntime::evaluateJavaScriptSimple

https://github.com/microsoft/react-native-windows/blob/392aa9ff15e58cc68b2c30db57fd57708c51756d/vnext/Shared/JSI/ChakraJsiRuntime_edgemode.cpp#L71-L72

It gets caught by ReactInstanceWin::OnError

https://github.com/microsoft/react-native-windows/blob/392aa9ff15e58cc68b2c30db57fd57708c51756d/vnext/Microsoft.ReactNative/ReactHost/ReactInstanceWin.cpp#L736-L738

which eventually ends up calling

https://github.com/microsoft/react-native-windows/blob/392aa9ff15e58cc68b2c30db57fd57708c51756d/vnext/Mso/src/debugAssertApi/debugAssertApi.cpp#L79-L82

But because we don't have any listeners set, nothing happens and the exception is just ignored.

I realize this exact repro was fixed in https://github.com/microsoft/react-native-windows/commit/7b2bcbb597ae8f2dae93d4a09cef6787cdb82903, but after talking with @acoates-ms, it sounds like there are other places calling AssertSz.

Full stack trace:

>	Microsoft.ReactNative.dll!MsoAssertSzTagProc(const _MsoAssertParams & params, const char * szFormat, char * argList) Line 105	C++
 	Microsoft.ReactNative.dll!MsoAssertSzTagProcInline(const _MsoAssertParams & params, const char * szFmt, ...) Line 92	C++
 	Microsoft.ReactNative.dll!`void <lambda>(const Mso::ErrorCode &)'::`1'::catch$1() Line 692	C++
 	[External Code]	
 	Microsoft.ReactNative.dll!Mso::React::GetDefaultOnErrorHandler::__l2::<lambda>(const Mso::ErrorCode & errorCode) Line 689	C++
 	Microsoft.ReactNative.dll!Mso::Details::StatelessFunctorWrapper<void <lambda>(const Mso::ErrorCode &),void,Mso::ErrorCode const &>::Invoke(const Mso::ErrorCode & <args_0>) Line 239	C++
 	Microsoft.ReactNative.dll!Mso::Functor<void __cdecl(Mso::ErrorCode const &)>::operator()(const Mso::ErrorCode & <args_0>) Line 412	C++
 	Microsoft.ReactNative.dll!Mso::React::ReactInstanceWin::OnError::__l2::<lambda>() Line 768	C++
 	Microsoft.ReactNative.dll!Mso::Internal::ActiveObjectBase::I`nvokeInQueue::__l2::<lambda>() Line 113	C++
 	Microsoft.ReactNative.dll!Mso::Details::FunctionObjectWrapper<void <lambda>(void),void>::Invoke() Line 166	C++
 	Microsoft.ReactNative.dll!Mso::QueueService::InvokeTask(Mso::Functor<void __cdecl(void)> && task, std::optional<std::chrono::time_point<std::chrono::steady_clock,std::chrono::duration<__int64,std::ratio<1,1000000000>>>> endTime) Line 208	C++
 	Microsoft.ReactNative.dll!Mso::ThreadPoolSchedulerWin::WorkCallback(_TP_CALLBACK_INSTANCE * __formal, void * context, _TP_WORK * __formal) Line 89	C++
 	[External Code]	

Environment

• npx react-native --version: 5.0.1
• npx react-native info:

  System:
      OS: Windows 10 10.0.19043
      CPU: (16) x64 Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz
      Memory: 4.31 GB / 15.87 GB
    Binaries:
      Node: 12.16.1 - C:\Program Files\nodejs\node.EXE
      Yarn: 1.22.5 - ~\scoop\apps\yarn\current\Yarn\bin\yarn.CMD
      npm: 7.20.2 - C:\Program Files\nodejs\npm.CMD
      Watchman: Not Found
    SDKs:
      Android SDK: Not Found
      Windows SDK:
        AllowDevelopmentWithoutDevLicense: Enabled
        AllowAllTrustedApps: Enabled
        Versions: 10.0.18362.0, 10.0.19041.0
    IDEs:
      Android Studio: Version  3.5.0.0 AI-191.8026.42.35.5900203
      Visual Studio: 16.10.31529.105 (Visual Studio Enterprise 2019), 16.10.31529.105 (Visual Studio Community 2019)
    Languages:
      Java: Not Found
    npmPackages:
      @react-native-community/cli: 5.0.1
      react: 17.0.1
      react-native: 0.64.2,
      react-native-windows: 0.64.14
    npmGlobalPackages:
      *react-native*: Not Found
  

Steps To Reproduce

git clone https://github.com/microsoft/rnx-kit.git
cd rnx-kit
git reset --hard c85e9aa2ea800dc137cbfe0d89e51ca2940e2516
yarn
cd packages/test-app
yarn build --dependencies
yarn install-windows-test-app
yarn windows

Expected Results

AssertSz should do something other than being silently discarded, e.g. throw or display a message.

Start with vnext/Mso/src/debugAssertApi/debugAssertApi.cpp and trace the AssertSz path from vnext/Shared/JSI/ChakraJsiRuntime_edgemode.cpp through vnext/Microsoft.ReactNative/ReactHost/ReactInstanceWin.cpp. Review other AssertSz callers and the existing error-handling path, then verify that relevant assertion failures are no longer silently discarded and that the behavior is covered by tests.