Fix undefined variable bug in debuginfotests lit.cfg.py

GitOrigin-RevId: 7ac4c31762fbe1605e2e701e4b48698f0f95a5c7
diff --git a/lit.cfg.py b/lit.cfg.py
index dd0b0f7..a8d23f3 100644
--- a/lit.cfg.py
+++ b/lit.cfg.py
@@ -87,6 +87,7 @@
 
 # Check which debuggers are available:
 built_lldb = llvm_config.use_llvm_tool('lldb', search_env='CLANG')
+lldb_path = None
 if built_lldb is not None:
     lldb_path = built_lldb
 elif lit.util.which('lldb') is not None: