AST: Don't trigger generic signature computation in ASTDumper

Author: slavapestov

lib/AST/ASTDumper.cpp

@@ -578,11 +578,6 @@ namespace {
     void printAbstractTypeParamCommon(AbstractTypeParamDecl *decl,
                                       const char *name) {
       printCommon(decl, name);
-      if (decl->getDeclContext()->getGenericEnvironmentOfContext()) {
-        if (auto superclassTy = decl->getSuperclass()) {
-          OS << " superclass='" << superclassTy->getString() << "'";
-        }
-      }
     }
 
     void visitGenericTypeParamDecl(GenericTypeParamDecl *decl) {