[clang] Fix contextual implicit conversions to int: with _Atomic (PR #203522)

[Shafik Yaghmour via cfe-commits]

================
@@ -7031,6 +7031,7 @@ ExprResult Sema::PerformContextualImplicitConversion(
   // Try converting the expression to an Lvalue first, to get rid of qualifiers.
   ExprResult Converted = DefaultLvalueConversion(From);
   QualType T = Converted.isUsable() ? Converted.get()->getType() : QualType();
+  From = Converted.get();
----------------
shafik wrote:

So above we check `Converted.isUsable()` does this matter here?

https://github.com/llvm/llvm-project/pull/203522