[content/test/gpu] Run pylint check of gpu tests in unittest instead of PRESUBMIT

third_party/logilab/logilab/astroid/brain/py2mechanize.py

+from astroid import MANAGER, register_module_extender
+from astroid.builder import AstroidBuilder
+
+def mechanize_transform():
+    return AstroidBuilder(MANAGER).string_build('''
+
+class Browser(object):
+    def open(self, url, data=None, timeout=None):
+        return None
+    def open_novisit(self, url, data=None, timeout=None):
+        return None
+    def open_local_file(self, filename):
+        return None
+
+''')
+
+
+register_module_extender(MANAGER, 'mechanize', mechanize_transform)