Revert "[clang] Fix of a crash 'Cannot get layout of forward declarations!' during CTU static analysis" (#156010)

Reverts #155375
Test does not work correctly on MacOS.

Author: balazske

clang/lib/AST/ASTImporter.cpp

@@ -1740,21 +1740,10 @@ ExpectedType ASTNodeImporter::VisitDeducedTemplateSpecializationType(
 }
 
 ExpectedType ASTNodeImporter::VisitTagType(const TagType *T) {
-  TagDecl *DeclForType = T->getOriginalDecl();
-  Expected<TagDecl *> ToDeclOrErr = import(DeclForType);
+  Expected<TagDecl *> ToDeclOrErr = import(T->getOriginalDecl());
   if (!ToDeclOrErr)
     return ToDeclOrErr.takeError();
 
-  if (DeclForType->isUsed()) {
-    // If there is a definition of the 'OriginalDecl', it should be imported to
-    // have all information for the type in the "To" AST. (In some cases no
-    // other reference may exist to the definition decl and it would not be
-    // imported otherwise.)
-    Expected<TagDecl *> ToDefDeclOrErr = import(DeclForType->getDefinition());
-    if (!ToDefDeclOrErr)
-      return ToDefDeclOrErr.takeError();
-  }
-
   if (T->isCanonicalUnqualified())
     return Importer.getToContext().getCanonicalTagType(*ToDeclOrErr);