caffe2: remove support for specifically running "flaky tests" (pytorch#112007)

Summary:
In March 2019 D14468816 introduced some infra to mark tests as flaky
while still running them. In July 2019 D15797371 removed the last use of this
feature. Remove the related code as well.

Test Plan: ci

Reviewed By: mlogachev

Differential Revision: D50601204

Pull Request resolved: pytorch#112007
Approved by: https://github.com/malfet

Author: asm89

caffe2/python/test_util.py

@@ -57,22 +57,6 @@ def get_default_test_flags():
     ]
 
 
-def caffe2_flaky(test_method):
-    # This decorator is used to mark a test method as flaky.
-    # This is used in conjunction with the environment variable
-    # CAFFE2_RUN_FLAKY_TESTS that specifies "flaky tests" mode
-    # If flaky tests mode are on, only flaky tests are run
-    # If flaky tests mode are off, only non-flaky tests are run
-    # NOTE: the decorator should be applied as the top-level decorator
-    # in a test method.
-    test_method.__caffe2_flaky__ = True
-    return test_method
-
-
-def is_flaky_test_mode():
-    return os.getenv('CAFFE2_RUN_FLAKY_TESTS', '0') == '1'
-
-
 class TestCase(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
@@ -82,15 +66,6 @@ def setUpClass(cls):
         core.SetEnginePref({}, {})
 
     def setUp(self):
-        # Skip tests based on whether we're in flaky test mode and
-        # the test is decorated as a flaky test.
-        test_method = getattr(self, self._testMethodName)
-        is_flaky_test = getattr(test_method, "__caffe2_flaky__", False)
-        if (is_flaky_test_mode() and not is_flaky_test):
-            raise unittest.SkipTest("Non-flaky tests are skipped in flaky test mode")
-        elif (not is_flaky_test_mode() and is_flaky_test):
-            raise unittest.SkipTest("Flaky tests are skipped in regular test mode")
-
         self.ws = workspace.C.Workspace()
         workspace.ResetWorkspace()