install_test: Add traceability to what tests are being run

Author: EricCousineau-TRI

tools/install/install_test.py

@@ -27,4 +27,5 @@ def test_install(self):
         # Execute the install actions.
         for cmd in lines:
             cmd = cmd.strip()
+            print("+ {}".format(cmd))
             install_test_helper.check_call(os.path.join(os.getcwd(), cmd))