Add _.support unit tests and remove _.support from the lodash underscore build.

Former-commit-id: 986c02d5363329f16cde720430b26edb6bc865f0

build.js

@@ -2432,6 +2432,9 @@
           });
         }());
 
+        // unexpose `lodash.support`
+        source = source.replace(/lodash\.support *= */, '');
+
         // remove `thisArg` from unexposed `forIn` and `forOwn`
         _.each([
           { 'methodName': 'forIn', 'flag': exposeForIn },