[llvm] [flang][runtime] fix intrinsics case of extends_type_of (PR #161466)

[Peter Klausler via llvm-commits]

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@@ -227,6 +227,7 @@ class Descriptor {
   RT_API_ATTRS bool IsPointer() const {
     return raw_.attribute == CFI_attribute_pointer;
   }
+  RT_API_ATTRS bool IsAssociated() const { return raw_.base_addr != nullptr; }
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klausler wrote:

`IsAllocated` does exist and it does the job.

https://github.com/llvm/llvm-project/pull/161466