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

R=danno@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10716004
Patch from Sigurður Ásgeirsson <siggi@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11944 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

tools/test-wrapper-gypbuild.py

@@ -217,9 +217,10 @@ 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 = [sys.executable]
   args_for_children += [workspace + '/tools/test.py'] + PassOnOptions(options)
   args_for_children += ['--no-build', '--build-system=gyp']
   for arg in args: