Update lit.cfg

Author: compnerd

test/lit.cfg

@@ -351,6 +351,7 @@ config.gyb = make_path(config.swift_utils, 'gyb.py')
 config.rth = make_path(config.swift_utils, 'rth') # Resilience test helper
 config.scale_test = make_path(config.swift_utils, 'scale-test')
 config.PathSanitizingFileCheck = make_path(config.swift_utils, 'PathSanitizingFileCheck')
+config.swift_bin_dir = make_path(config.swift, '..', '..', 'bin')
 config.swift_lib_dir = make_path(config.swift, '..', '..', 'lib')
 config.round_trip_syntax_test = make_path(config.swift_utils, 'round-trip-syntax-test')
 config.refactor_check_compiles = make_path(config.swift_utils, 'refactor-check-compiles.py')