[clang] [clang] Fix the crash when dumping deserialized decls (PR #133395)

[Ilya Biryukov via cfe-commits]

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@@ -57,6 +59,8 @@ class ASTDeserializationListener {
   /// A module import was read from the AST file.
   virtual void ModuleImportRead(serialization::SubmoduleID ID,
                                 SourceLocation ImportLoc) {}
+  /// The deserialization of the AST file was finished.
+  virtual void FinishedDeserializing() {}
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ilya-biryukov wrote:

We should also have `StartDeserializing` in the interface or none of the two.
This should help with the reentrancy question for the implementation that I have below too.

https://github.com/llvm/llvm-project/pull/133395