Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto

Index: third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto
diff --git a/third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto b/third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto
deleted file mode 100644
index 8b2d9658880af11ed7edd4e98db6a0d67c89486e..0000000000000000000000000000000000000000
--- a/third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_singular_nano.proto
+++ /dev/null
@@ -1,34 +0,0 @@
-syntax = "proto2";
-
-option java_multiple_files = true;
-option java_package = "com.google.protobuf";
-
-import "google/protobuf/nano/unittest_extension_nano.proto";
-
-// Must be compiled separately due to extension number reuse.
-// The reuse is deliberate, for testing wire compatibility.
-
-message SingularExtensions {
-  extend ExtendableMessage {
-    optional int32          some_int32    = 10;
-    optional uint32         some_uint32   = 11;
-    optional sint32         some_sint32   = 12;
-    optional int64          some_int64    = 13;
-    optional uint64         some_uint64   = 14;
-    optional sint64         some_sint64   = 15;
-    optional fixed32        some_fixed32  = 16;
-    optional sfixed32       some_sfixed32 = 17;
-    optional fixed64        some_fixed64  = 18;
-    optional sfixed64       some_sfixed64 = 19;
-    optional bool           some_bool     = 20;
-    optional float          some_float    = 21;
-    optional double         some_double   = 22;
-    optional AnEnum         some_enum     = 23;
-    optional string         some_string   = 24;
-    optional bytes          some_bytes    = 25;
-    optional AnotherMessage some_message  = 26;
-    optional group          SomeGroup     = 27 {
-      optional int32 a = 1;
-    }
-  }
-}