add test tags

tests/run/knuth_man_or_boy_test.pyx

-#
+# mode: run
+# tag: closures
+
 # Cython version of Knuth's "man or boy" test -- "It separates the man
 # Algol 60 compilers from the boy Algol 60 compilers." Here's the
 # original (from wikipedia):

tests/run/lambda_tests.pyx

-#
-# lambda_tests.pyx
-#
+# mode: run
+# tag: closures, lambda
+
 # Battery of tests for closures in Cython. Based on the collection of
 # compiler tests from P423/B629 at Indiana University, Spring 1999 and
 # Fall 2000. Special thanks to R. Kent Dybvig, Dan Friedman, Kevin