[llvm] Set ObjectFile's assignment operator to also be deleted like its copy constructor (PR #92942)

[via llvm-commits]

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@@ -302,6 +302,7 @@ class ObjectFile : public SymbolicFile {
 public:
   ObjectFile() = delete;
   ObjectFile(const ObjectFile &other) = delete;
+  ObjectFile operator=(const ObjectFile &other) = delete;
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dyung wrote:

This should probably be `&operator` and not `&opeartor`. I think this typo is causing nearly every buildbot to fail.

https://github.com/llvm/llvm-project/pull/92942