[clang][NFC] Cleanup some coroutine tests

I noticed these two tests emit a warning about a missing
unhandled_exception.  That's irrelevant to what is being tested, but
is unnecessary noise.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D125535

clang/test/CodeGenCoroutines/coro-ret-void.cpp

@@ -8,6 +8,7 @@ struct coro1 {
     std::suspend_never initial_suspend();
     std::suspend_never final_suspend() noexcept;
     void return_void();
+    void unhandled_exception() noexcept;
   };
 };
 
@@ -39,6 +40,7 @@ struct coro2 {
     std::suspend_never initial_suspend();
     std::suspend_never final_suspend() noexcept;
     void return_value(int);
+    void unhandled_exception() noexcept;
   };
 };
 

clang/test/CoverageMapping/coroutine.cpp

@@ -30,6 +30,7 @@ struct std::coroutine_traits<int, int> {
     int get_return_object();
     suspend_always initial_suspend();
     suspend_always final_suspend() noexcept;
+    void unhandled_exception() noexcept;
     void return_value(int);
   };
 };