[clang] [clang] fix sema init crash for not checking a ExprResult (PR #98102)

[Yuxuan Chen via cfe-commits]

================
@@ -5576,6 +5576,10 @@ static void TryOrBuildParenListInitialization(
       ExprResult ER;
       ER = IS.Perform(S, SubEntity, SubKind,
                       Arg ? MultiExprArg(Arg) : std::nullopt);
+
+      if (ER.isInvalid())
----------------
yuxuanchen1997 wrote:

If you look at `InitializationSequence::Perform` (this function is 1000 lines long), it first checks `Failed()` then proceed to build a whole bunch of things. There are a couple of places it returned `ExprError`. I think it's possible to still be invalid after `!Failed()`. 

https://github.com/llvm/llvm-project/pull/98102