[clang] [Clang] Fix crash involving `__attribute__((cleanup))` attributes and improve handling of multiple `cleanup` attributes (PR #207785)

[Aaron Ballman via cfe-commits]

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@@ -0,0 +1,53 @@
+// RUN: %clang_cc1 -std=c11 -emit-llvm -o - -triple x86_64-unknown-linux %s | FileCheck %s
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AaronBallman wrote:

```suggestion
// RUN: %clang_cc1 -emit-llvm -o - -triple x86_64-unknown-linux %s | FileCheck %s
```
I don't think we need a standards mode for this one, right?

https://github.com/llvm/llvm-project/pull/207785