Add missing "import testing"

Author: igaztanaga

test/Jamfile.v2

@@ -15,6 +15,8 @@
 # the run rule for each source, the result is a list of all
 # the run rules, which we can pass on to the test_suite rule:
 
+import testing ;
+
 project : requirements
     <library>/boost/interprocess//boost_interprocess
     #<library>/boost/date_time//boost_date_time