Add break for default cases

Visual Studio has an option to search all files in a solution, so I
did a search in there for "default:" looking for any missing break
statements.

I've left out default statements that return something, and that throw
something, even if via ThrowInvalidType. UNREACHABLE leads towards throw

R_THROW macro leads towards a return

src/common/atomic_helpers.h

@@ -156,6 +156,7 @@ AE_FORCEINLINE void compiler_fence(memory_order order) AE_NO_TSAN {
         break;
     default:
         assert(false);
+        break;
     }
 }