[clang] [analyzer] Match dangling subobjects by their base region in DanglingPtrDeref (PR #211552)

[via cfe-commits]

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@@ -112,3 +112,105 @@ void inlined_callee_single_report() {
   // expected-note at -1 {{Calling 'deref_param'}}
   (void)r;
 }
+
+struct MyBuffer {
+  char buffer[8];
+};
+struct MyStruct { int x; };
+struct Inner { int x; };
+struct Outer { struct Inner inner; };
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isuckatcs wrote:

```suggestion
struct Outer { Inner inner; };
```

I'm not sure if we should spell out `struct` in C++ (this applies to every other place in this test file as well). 

Also, what if `Inner` is declared inside `Outer`?
```c++
struct Outer {
  struct Inner {};
};
```

https://github.com/llvm/llvm-project/pull/211552