Allow using test-wrapper-gypbuild.py on Windows when no python interpreter is registered.

tools/test-wrapper-gypbuild.py

Index: tools/test-wrapper-gypbuild.py
diff --git a/tools/test-wrapper-gypbuild.py b/tools/test-wrapper-gypbuild.py
index d99d055e5010e28bd0adae4347e9ea5800041f33..6e5fdcffdc4af53014d558fa07b89e308691b0c4 100755
--- a/tools/test-wrapper-gypbuild.py
+++ b/tools/test-wrapper-gypbuild.py
@@ -217,7 +217,8 @@ def Main():
 
   if not options.no_presubmit:
     print ">>> running presubmit tests"
-    returncodes += subprocess.call([workspace + '/tools/presubmit.py'])
+    returncodes += subprocess.call([sys.executable, 
+                                    workspace + '/tools/presubmit.py'])
 
   args_for_children = ['python']
   args_for_children += [workspace + '/tools/test.py'] + PassOnOptions(options)