Revert "[clang] Prevent that Decl::dump on a CXXRecordDecl deserialises further declarations."

This reverts commit 0478720157f6413fad7595b8eff9c70d2d99b637. This probably
doesn't work when forcing deserialising while dumping (which the ASTDumper
optionally supports).
diff --git a/clang/lib/AST/TextNodeDumper.cpp b/clang/lib/AST/TextNodeDumper.cpp
index 19b7b4c..16c4c37 100644
--- a/clang/lib/AST/TextNodeDumper.cpp
+++ b/clang/lib/AST/TextNodeDumper.cpp
@@ -1960,11 +1960,7 @@
       FLAG(hasTrivialDestructor, trivial);
       FLAG(hasNonTrivialDestructor, non_trivial);
       FLAG(hasUserDeclaredDestructor, user_declared);
-      // Avoid calls to the external source.
-      if (!D->hasExternalVisibleStorage()) {
-        FLAG(hasConstexprDestructor, constexpr);
-      } else
-        OS << " maybe_constexpr";
+      FLAG(hasConstexprDestructor, constexpr);
       FLAG(needsImplicitDestructor, needs_implicit);
       FLAG(needsOverloadResolutionForDestructor, needs_overload_resolution);
       if (!D->needsOverloadResolutionForDestructor())