Disable VarIntCoder for long values

----Release Notes----
[]
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=117511153

Author: charlesccychen

google/cloud/dataflow/coders/typecoders.py

@@ -78,7 +78,6 @@ def __init__(self, fallback_coder=None):
   def register_standard_coders(self, fallback_coder):
     """Register coders for all basic and composite types."""
     self._register_coder_internal(int, coders.VarIntCoder)
-    self._register_coder_internal(long, coders.VarIntCoder)
     self._register_coder_internal(float, coders.FloatCoder)
     self._register_coder_internal(str, coders.BytesCoder)
     self._register_coder_internal(bytes, coders.BytesCoder)

google/cloud/dataflow/coders/typecoders_test.py

@@ -90,9 +90,6 @@ def test_standard_int_coder(self):
     self.assertEqual(
         real_coder.encode(0x0404), expected_coder.encode(0x0404))
     self.assertEqual(0x0404, real_coder.decode(real_coder.encode(0x0404)))
-
-    real_coder = typecoders.registry.get_coder(long)
-    expected_coder = coders.VarIntCoder()
     self.assertEqual(
         real_coder.encode(0x040404040404),
         expected_coder.encode(0x040404040404))