Reverts third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/map_proto2_unittest.proto

Index: third_party/protobuf/src/google/protobuf/map_proto2_unittest.proto
diff --git a/third_party/protobuf/src/google/protobuf/map_proto2_unittest.proto b/third_party/protobuf/src/google/protobuf/map_proto2_unittest.proto
index e9360a5a6870624132b938e858e7ad0fc1d014e5..916cc54637538cb4e4a28b7c617dcbebd4b846a5 100644
--- a/third_party/protobuf/src/google/protobuf/map_proto2_unittest.proto
+++ b/third_party/protobuf/src/google/protobuf/map_proto2_unittest.proto
@@ -29,7 +29,7 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 syntax = "proto2";
-option cc_enable_arenas = true;
+
 
 import "google/protobuf/unittest_import.proto";
 
@@ -64,23 +64,3 @@ message TestEnumMapPlusExtra {
 message TestImportEnumMap {
   map<int32, protobuf_unittest_import.ImportEnumForMap> import_enum_amp = 1;
 }
-
-message TestIntIntMap {
-  map<int32, int32> m = 1;
-}
-
-// Test all key types: string, plus the non-floating-point scalars.
-message TestMaps {
-  map<int32, TestIntIntMap> m_int32 = 1;
-  map<int64, TestIntIntMap> m_int64 = 2;
-  map<uint32, TestIntIntMap> m_uint32 = 3;
-  map<uint64, TestIntIntMap> m_uint64 = 4;
-  map<sint32, TestIntIntMap> m_sint32 = 5;
-  map<sint64, TestIntIntMap> m_sint64 = 6;
-  map<fixed32, TestIntIntMap> m_fixed32 = 7;
-  map<fixed64, TestIntIntMap> m_fixed64 = 8;
-  map<sfixed32, TestIntIntMap> m_sfixed32 = 9;
-  map<sfixed64, TestIntIntMap> m_sfixed64 = 10;
-  map<bool, TestIntIntMap> m_bool = 11;
-  map<string, TestIntIntMap> m_string = 12;
-}