[lit] Add missing os.path.normcase() to config-map-discovery test

5ccfa15 removed normalization from abs_path_preserve_drive but I missed adding this case back to the caller

Author: RKSimon

llvm/utils/lit/tests/Inputs/config-map-discovery/driver.py

@@ -3,6 +3,7 @@
 import sys
 
 main_config = lit.util.abs_path_preserve_drive(sys.argv[1])
+main_config = os.path.normcase(main_config)
 
 config_map = {main_config: sys.argv[2]}
 builtin_parameters = {"config_map": config_map}