[unittests] Fix TableGenTests with LLVM_LINK_LLVM_DYLIB (#86664)

Since the restructuring in commit fa3d789, the option
DISABLE_LLVM_LINK_LLVM_DYLIB is counter-productive and leads to
CommandLine Error: Option 'debug-counter' registered more than once!

Author: hahnjo

llvm/unittests/TableGen/CMakeLists.txt

@@ -9,7 +9,7 @@ tablegen(LLVM AutomataTables.inc -gen-searchable-tables)
 tablegen(LLVM AutomataAutomata.inc -gen-automata)
 add_public_tablegen_target(AutomataTestTableGen)
 
-add_llvm_unittest(TableGenTests DISABLE_LLVM_LINK_LLVM_DYLIB
+add_llvm_unittest(TableGenTests
   AutomataTest.cpp
   CodeExpanderTest.cpp
   ParserEntryPointTest.cpp