Exclude addressbook.proto from C# boostrap test.

This addressbook.proto now belongs to its own bazel pacakge and can't be
accessed in bazel protobuf_test target.

BUILD

@@ -615,7 +615,6 @@ cc_test(
         # Files for csharp_bootstrap_unittest.cc.
         "conformance/**/*",
         "csharp/src/**/*",
-        "examples/**/*",
     ]),
     includes = [
         "src/",

src/google/protobuf/compiler/csharp/csharp_bootstrap_unittest.cc

@@ -184,11 +184,6 @@ TEST(CsharpBootstrapTest, GeneratedCsharpDescriptorMatches) {
                     "../csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs");
 
   generate_test.SetParameter("");
-  source_tree.MapPath("", TestSourceDir() + "/../examples");
-  generate_test.Run(importer.Import("addressbook.proto"),
-                    "Addressbook.cs",
-                    "../csharp/src/AddressBook/Addressbook.cs");
-
   source_tree.MapPath("", TestSourceDir() + "/../conformance");
   generate_test.Run(importer.Import("conformance.proto"),
                     "Conformance.cs",