Print a message if lit detects the swift benchmarks are usable for integration testing.

Author: gottesmm

lit.cfg

@@ -162,6 +162,7 @@ if swift_benchmarks_path is None:
 if os.path.exists(swift_benchmarks_path):
     config.available_features.add("have-swift-benchmarks")
     config.substitutions.append( ('%{swift_benchmarks_path}', swift_benchmarks_path) )
+    lit_config.note('testing using swift benchmarks at path: {}'.format(swift_benchmarks_path))
 
 # Find the tools we need.